Adding Example app

.gitignore

@@ -1,4 +1,5 @@
 .idea
+example/venv
 # Byte-compiled / optimized / DLL files
 __pycache__/
 *.py[cod]

EXAMPLE.md

@@ -0,0 +1,8 @@
+# Use of Example project
+
+1. create virtual env
+`virtualenv venv`
+1. activate env `source venv/bin/activate`
+1. install requirements `pip install -r requirements.txt`
+1. migrate `python manage.py migrate`
+1. create super user 'python manage.py createsuperuser' 

README.md

@@ -7,9 +7,14 @@ Web Authencation API (WebAuthn) is state-of-the art techology that is expected t
 
 ![Andriod Fingerprint](https://cdn-images-1.medium.com/max/800/1*1FWkRE8D7NTA2Kn1DrPjPA.png)
 
-For FIDO2, **security keys**, **Apple's Touch ID (Chrome)** and **android-safetynet** are supported.
+For FIDO2, the following are supported
+ * **security keys** (Firefox 60+, Chrome 67+, Edge 18+),
+ * **Windows Hello** (Firefox 67+, Chrome 72+ , Edge) ,
+ * **Apple's Touch ID** (Chrome 70+ on Mac OS X ),
+ * **android-safetynet** (Chrome 70+)
+ * **NFC devices using PCSC** (Not Tested, but as supported in fido2)
 
-In English :), It allows you to verify the user by security keys on PC, Laptops, Touch ID on Macboks (Chrome) and Fingerprint/PIN on Andriod Phones.
+In English :), It allows you to verify the user by security keys on PC, Laptops or Mobiles, Windows Hello (Fingerprint, PIN) on Windows 10 Build 1903+ (May 2019 Update) Touch ID on Macbooks (Chrome) and Fingerprint/Face/Iris/PIN on Andriod Phones.
 
 Trusted device is a mode for the user to add a device that doesn't support security keys like iOS and andriod without fingerprints or NFC.
 
@@ -24,7 +29,7 @@ Depends on
 * ua-parser
 * user-agents
 * python-jose
-* fido2==0.5
+* fido2==0.7
 
 
 # Installation
@@ -36,6 +41,8 @@ Depends on
    'mfa',
    '......')
    ```
+1. Collect Static Files
+`python manage.py collectstatic`
 1. Add the following settings to your file
 
    ```python 
@@ -45,6 +52,7 @@ Depends on
    MFA_RECHECK_MIN=10         # Minimum interval in seconds
    MFA_RECHECK_MAX=30         # Maximum in seconds
    MFA_QUICKLOGIN=True        # Allow quick login for returning users by provide only their 2FA
+   MFA_HIDE_DISABLE=('FIDO2',)     # Can the user disable his key (Added in 1.2.0).   
 
    TOKEN_ISSUER_NAME="PROJECT_NAME"      #TOTP Issuer name
 

example/example/auth.py

@@ -0,0 +1,30 @@
+from django.shortcuts import render
+from django.http import HttpResponseRedirect
+from django.urls import reverse
+from django.contrib.auth import authenticate,login,logout
+from django.contrib.auth.models import User
+def loginView(request):
+    context={}
+    if request.method=="POST":
+        username=request.POST["username"]
+        password=request.POST["password"]
+        user=authenticate(username=username,password=password)
+        if user:
+            from mfa.helpers import has_mfa
+            res = has_mfa(username = username, request = request)  # has_mfa returns false or HttpResponseRedirect
+            if res:
+                return res
+            return create_session(request,user.username)
+        context["invalid"]=True
+    return render(request, "login.html", context)
+
+def create_session(request,username):
+    user=User.objects.get(username=username)
+    user.backend='django.contrib.auth.backends.ModelBackend'
+    login(request, user)
+    return HttpResponseRedirect(reverse('home'))
+
+
+def logoutView(request):
+    logout(request)
+    return  render(request,"logout.html",{})

example/example/settings.py

@@ -0,0 +1,148 @@
+"""
+Django settings for example project.
+
+Generated by 'django-admin startproject' using Django 2.0.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.0/topics/settings/
+
+For the full list of settings and their values, see
+https://docs.djangoproject.com/en/2.0/ref/settings/
+"""
+
+import os
+
+# Build paths inside the project like this: os.path.join(BASE_DIR, ...)
+BASE_DIR = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+
+
+# Quick-start development settings - unsuitable for production
+# See https://docs.djangoproject.com/en/2.0/howto/deployment/checklist/
+
+# SECURITY WARNING: keep the secret key used in production secret!
+SECRET_KEY = '#9)q!_i3@pr-^3oda(e^3$x!kq3b4f33#5l@+=+&vuz+p6gb3g'
+
+# SECURITY WARNING: don't run with debug turned on in production!
+DEBUG = True
+
+ALLOWED_HOSTS = []
+
+
+# Application definition
+
+INSTALLED_APPS = [
+    'django.contrib.admin',
+    'django.contrib.auth',
+    'django.contrib.contenttypes',
+    'django.contrib.sessions',
+    'django.contrib.messages',
+    'django.contrib.staticfiles',
+    'mfa',
+    'sslserver'
+]
+
+MIDDLEWARE = [
+    'django.middleware.security.SecurityMiddleware',
+    'django.contrib.sessions.middleware.SessionMiddleware',
+    'django.middleware.common.CommonMiddleware',
+    'django.middleware.csrf.CsrfViewMiddleware',
+    'django.contrib.auth.middleware.AuthenticationMiddleware',
+    'django.contrib.messages.middleware.MessageMiddleware',
+    'django.middleware.clickjacking.XFrameOptionsMiddleware',
+]
+
+ROOT_URLCONF = 'example.urls'
+
+TEMPLATES = [
+    {
+        'BACKEND': 'django.template.backends.django.DjangoTemplates',
+        'DIRS': [os.path.join(BASE_DIR ,'example','templates' )],
+        'APP_DIRS': True,
+        'OPTIONS': {
+            'context_processors': [
+                'django.template.context_processors.debug',
+                'django.template.context_processors.request',
+                'django.contrib.auth.context_processors.auth',
+                'django.contrib.messages.context_processors.messages',
+            ],
+        },
+    },
+]
+
+WSGI_APPLICATION = 'example.wsgi.application'
+
+
+# Database
+# https://docs.djangoproject.com/en/2.0/ref/settings/#databases
+
+DATABASES = {
+    'default': {
+        'ENGINE': 'django.db.backends.sqlite3',
+        'NAME': os.path.join(BASE_DIR, 'db.sqlite3'),
+    }
+}
+
+
+# Password validation
+# https://docs.djangoproject.com/en/2.0/ref/settings/#auth-password-validators
+
+AUTH_PASSWORD_VALIDATORS = [
+    {
+        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
+    },
+    {
+        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
+    },
+]
+
+
+# Internationalization
+# https://docs.djangoproject.com/en/2.0/topics/i18n/
+
+LANGUAGE_CODE = 'en-us'
+
+TIME_ZONE = 'UTC'
+
+USE_I18N = True
+
+USE_L10N = True
+
+USE_TZ = True
+
+
+# Static files (CSS, JavaScript, Images)
+# https://docs.djangoproject.com/en/2.0/howto/static-files/
+
+STATIC_URL = '/static/'
+#STATIC_ROOT=(os.path.join(BASE_DIR,'static'))
+STATICFILES_DIRS=[os.path.join(BASE_DIR,'static')]
+LOGIN_URL="/auth/login"
+
+EMAIL_FROM='Test App'
+EMAIL_HOST="smtp.gmail.com"
+EMAIL_PORT=587
+EMAIL_HOST_USER="mkalioby@gmail.com"
+EMAIL_HOST_PASSWORD='wanted85'
+EMAIL_USE_TLS=True
+
+
+
+MFA_UNALLOWED_METHODS=()   # Methods that shouldn't be allowed for the user
+MFA_LOGIN_CALLBACK="example.auth.create_session"      # A function that should be called by username to login the user in session
+MFA_RECHECK=True           # Allow random rechecking of the user
+MFA_RECHECK_MIN=10         # Minimum interval in seconds
+MFA_RECHECK_MAX=30         # Maximum in seconds
+MFA_QUICKLOGIN=True        # Allow quick login for returning users by provide only their 2FA
+MFA_HIDE_DISABLE=('FIDO2',)     # Can the user disable his key (Added in 1.2.0).
+
+TOKEN_ISSUER_NAME="PROJECT_NAME"      #TOTP Issuer name
+
+U2F_APPID="https://localhost"    #URL For U2F
+FIDO_SERVER_ID=u"localhost"      # Server rp id for FIDO2, it the full domain of your project
+FIDO_SERVER_NAME=u"PROJECT_NAME"

example/example/templates/base.html

@@ -0,0 +1,156 @@
+{% load static %}
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+  <meta name="description" content="">
+  <meta name="author" content="">
+
+  <title>SB Admin - Blank Page</title>
+
+  <!-- Custom fonts for this template-->
+  <link href="{% static 'vendor/fontawesome-free/css/all.min.css'%}" rel="stylesheet" type="text/css">
+
+  <!-- Page level plugin CSS-->
+  <link href="{% static 'vendor/datatables/dataTables.bootstrap4.css'%}" rel="stylesheet">
+
+  <!-- Custom styles for this template-->
+  <link href="{% static 'css/sb-admin.css'%}" rel="stylesheet">
+    <script src="{% static 'vendor/jquery/jquery.min.js'%}"></script>
+
+</head>
+
+<body id="page-top">
+
+  <nav class="navbar navbar-expand navbar-dark bg-dark static-top">
+      <button class="btn btn-link btn-sm text-white order-1 order-sm-0" id="sidebarToggle" href="#">
+      <i class="fas fa-bars"></i>
+    </button>
+    <a class="navbar-brand mr-1" href="index.html">Django-mfa2</a>
+
+
+
+    <!-- Navbar Search -->
+    <form class="d-none d-md-inline-block form-inline ml-auto mr-0 mr-md-3 my-2 my-md-0">
+      <div class="input-group">
+        <input type="text" class="form-control" placeholder="Search for..." aria-label="Search" aria-describedby="basic-addon2">
+        <div class="input-group-append">
+          <button class="btn btn-primary" type="button">
+            <i class="fas fa-search"></i>
+          </button>
+        </div>
+      </div>
+    </form>
+
+    <!-- Navbar -->
+    <ul class="navbar-nav ml-auto ml-md-0">
+      <li class="nav-item dropdown no-arrow mx-1">
+        <a class="nav-link dropdown-toggle" href="#" id="alertsDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-bell fa-fw"></i>
+          <span class="badge badge-danger"></span>
+        </a>
+        <div class="dropdown-menu dropdown-menu-right" aria-labelledby="alertsDropdown">
+          <a class="dropdown-item" href="#">Action</a>
+          <a class="dropdown-item" href="#">Another action</a>
+          <div class="dropdown-divider"></div>
+          <a class="dropdown-item" href="#">Something else here</a>
+        </div>
+      </li>
+
+      <li class="nav-item dropdown no-arrow">
+        <a class="nav-link dropdown-toggle" href="#" id="userDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-user-circle fa-fw"></i>&nbsp;{{ request.user.username }}
+        </a>
+        <div class="dropdown-menu dropdown-menu-right" aria-labelledby="userDropdown">
+          <a class="dropdown-item" href="#">Settings</a>
+          <a class="dropdown-item" href="{% url 'mfa_home' %}">Security</a>
+          <a class="dropdown-item" href="#">Activity Log</a>
+          <div class="dropdown-divider"></div>
+          <a class="dropdown-item" href="#" data-toggle="modal" data-target="#logoutModal">Logout</a>
+        </div>
+
+      </li>
+    </ul>
+
+  </nav>
+
+  <div id="wrapper">
+
+    <!-- Sidebar -->
+    <ul class="sidebar navbar-nav">
+      <li class="nav-item">
+        <a class="nav-link" href="index.html">
+          <i class="fas fa-fw fa-tachometer-alt"></i>
+          <span>Dashboard</span>
+        </a>
+      </li>
+
+    </ul>
+
+    <div id="content-wrapper">
+
+      <div class="container-fluid">
+
+        <!-- Breadcrumbs-->
+        {% block content %}
+        {% endblock %}
+
+      </div>
+      <!-- /.container-fluid -->
+
+      <!-- Sticky Footer -->
+      <footer class="sticky-footer">
+        <div class="container my-auto">
+          <div class="copyright text-center my-auto">
+            <span>Copyright © Your Website 2019</span>
+          </div>
+        </div>
+      </footer>
+
+    </div>
+    <!-- /.content-wrapper -->
+
+  </div>
+  <!-- /#wrapper -->
+
+  <!-- Scroll to Top Button-->
+  <a class="scroll-to-top rounded" href="#page-top">
+    <i class="fas fa-angle-up"></i>
+  </a>
+
+  <!-- Logout Modal-->
+  <div class="modal fade" id="logoutModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
+    <div class="modal-dialog" role="document">
+      <div class="modal-content">
+        <div class="modal-header">
+          <h5 class="modal-title" id="exampleModalLabel">Ready to Leave?</h5>
+          <button class="close" type="button" data-dismiss="modal" aria-label="Close">
+            <span aria-hidden="true">×</span>
+          </button>
+        </div>
+        <div class="modal-body">Select "Logout" below if you are ready to end your current session.</div>
+        <div class="modal-footer">
+          <button class="btn btn-secondary" type="button" data-dismiss="modal">Cancel</button>
+          <a class="btn btn-primary" href="{% url 'logout' %}">Logout</a>
+        </div>
+      </div>
+    </div>
+  </div>
+
+  <!-- Bootstrap core JavaScript-->
+  <script src="{% static 'vendor/bootstrap/js/bootstrap.bundle.min.js'%}"></script>
+
+  <!-- Core plugin JavaScript-->
+  <script src="{%static 'vendor/jquery-easing/jquery.easing.min.js'%}"></script>
+
+  <!-- Custom scripts for all pages-->
+  <script src="{% static 'js/sb-admin.min.js'%}"></script>
+    {% block head %}
+    {% endblock %}
+</body>
+
+</html>

example/example/templates/blank.html

@@ -0,0 +1,197 @@
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+  <meta name="description" content="">
+  <meta name="author" content="">
+
+  <title>SB Admin - Blank Page</title>
+
+  <!-- Custom fonts for this template-->
+  <link href="vendor/fontawesome-free/css/all.min.css" rel="stylesheet" type="text/css">
+
+  <!-- Page level plugin CSS-->
+  <link href="vendor/datatables/dataTables.bootstrap4.css" rel="stylesheet">
+
+  <!-- Custom styles for this template-->
+  <link href="css/sb-admin.css" rel="stylesheet">
+
+</head>
+
+<body id="page-top">
+
+  <nav class="navbar navbar-expand navbar-dark bg-dark static-top">
+
+    <a class="navbar-brand mr-1" href="index.html">Start Bootstrap</a>
+
+    <button class="btn btn-link btn-sm text-white order-1 order-sm-0" id="sidebarToggle" href="#">
+      <i class="fas fa-bars"></i>
+    </button>
+
+    <!-- Navbar Search -->
+    <form class="d-none d-md-inline-block form-inline ml-auto mr-0 mr-md-3 my-2 my-md-0">
+      <div class="input-group">
+        <input type="text" class="form-control" placeholder="Search for..." aria-label="Search" aria-describedby="basic-addon2">
+        <div class="input-group-append">
+          <button class="btn btn-primary" type="button">
+            <i class="fas fa-search"></i>
+          </button>
+        </div>
+      </div>
+    </form>
+
+    <!-- Navbar -->
+    <ul class="navbar-nav ml-auto ml-md-0">
+      <li class="nav-item dropdown no-arrow mx-1">
+        <a class="nav-link dropdown-toggle" href="#" id="alertsDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-bell fa-fw"></i>
+          <span class="badge badge-danger">9+</span>
+        </a>
+        <div class="dropdown-menu dropdown-menu-right" aria-labelledby="alertsDropdown">
+          <a class="dropdown-item" href="#">Action</a>
+          <a class="dropdown-item" href="#">Another action</a>
+          <div class="dropdown-divider"></div>
+          <a class="dropdown-item" href="#">Something else here</a>
+        </div>
+      </li>
+      <li class="nav-item dropdown no-arrow mx-1">
+        <a class="nav-link dropdown-toggle" href="#" id="messagesDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-envelope fa-fw"></i>
+          <span class="badge badge-danger">7</span>
+        </a>
+        <div class="dropdown-menu dropdown-menu-right" aria-labelledby="messagesDropdown">
+          <a class="dropdown-item" href="#">Action</a>
+          <a class="dropdown-item" href="#">Another action</a>
+          <div class="dropdown-divider"></div>
+          <a class="dropdown-item" href="#">Something else here</a>
+        </div>
+      </li>
+      <li class="nav-item dropdown no-arrow">
+        <a class="nav-link dropdown-toggle" href="#" id="userDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-user-circle fa-fw"></i>
+        </a>
+        <div class="dropdown-menu dropdown-menu-right" aria-labelledby="userDropdown">
+          <a class="dropdown-item" href="#">Settings</a>
+          <a class="dropdown-item" href="#">Activity Log</a>
+          <div class="dropdown-divider"></div>
+          <a class="dropdown-item" href="#" data-toggle="modal" data-target="#logoutModal">Logout</a>
+        </div>
+      </li>
+    </ul>
+
+  </nav>
+
+  <div id="wrapper">
+
+    <!-- Sidebar -->
+    <ul class="sidebar navbar-nav">
+      <li class="nav-item">
+        <a class="nav-link" href="index.html">
+          <i class="fas fa-fw fa-tachometer-alt"></i>
+          <span>Dashboard</span>
+        </a>
+      </li>
+      <li class="nav-item dropdown">
+        <a class="nav-link dropdown-toggle" href="#" id="pagesDropdown" role="button" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
+          <i class="fas fa-fw fa-folder"></i>
+          <span>Pages</span>
+        </a>
+        <div class="dropdown-menu" aria-labelledby="pagesDropdown">
+          <h6 class="dropdown-header">Login Screens:</h6>
+          <a class="dropdown-item" href="login.html">Login</a>
+          <a class="dropdown-item" href="register.html">Register</a>
+          <a class="dropdown-item" href="forgot-password.html">Forgot Password</a>
+          <div class="dropdown-divider"></div>
+          <h6 class="dropdown-header">Other Pages:</h6>
+          <a class="dropdown-item" href="404.html">404 Page</a>
+          <a class="dropdown-item active" href="blank.html">Blank Page</a>
+        </div>
+      </li>
+      <li class="nav-item">
+        <a class="nav-link" href="charts.html">
+          <i class="fas fa-fw fa-chart-area"></i>
+          <span>Charts</span></a>
+      </li>
+      <li class="nav-item">
+        <a class="nav-link" href="tables.html">
+          <i class="fas fa-fw fa-table"></i>
+          <span>Tables</span></a>
+      </li>
+    </ul>
+
+    <div id="content-wrapper">
+
+      <div class="container-fluid">
+
+        <!-- Breadcrumbs-->
+        <ol class="breadcrumb">
+          <li class="breadcrumb-item">
+            <a href="index.html">Dashboard</a>
+          </li>
+          <li class="breadcrumb-item active">Blank Page</li>
+        </ol>
+
+        <!-- Page Content -->
+        <h1>Blank Page</h1>
+        <hr>
+        <p>This is a great starting point for new custom pages.</p>
+
+      </div>
+      <!-- /.container-fluid -->
+
+      <!-- Sticky Footer -->
+      <footer class="sticky-footer">
+        <div class="container my-auto">
+          <div class="copyright text-center my-auto">
+            <span>Copyright © Your Website 2019</span>
+          </div>
+        </div>
+      </footer>
+
+    </div>
+    <!-- /.content-wrapper -->
+
+  </div>
+  <!-- /#wrapper -->
+
+  <!-- Scroll to Top Button-->
+  <a class="scroll-to-top rounded" href="#page-top">
+    <i class="fas fa-angle-up"></i>
+  </a>
+
+  <!-- Logout Modal-->
+  <div class="modal fade" id="logoutModal" tabindex="-1" role="dialog" aria-labelledby="exampleModalLabel" aria-hidden="true">
+    <div class="modal-dialog" role="document">
+      <div class="modal-content">
+        <div class="modal-header">
+          <h5 class="modal-title" id="exampleModalLabel">Ready to Leave?</h5>
+          <button class="close" type="button" data-dismiss="modal" aria-label="Close">
+            <span aria-hidden="true">×</span>
+          </button>
+        </div>
+        <div class="modal-body">Select "Logout" below if you are ready to end your current session.</div>
+        <div class="modal-footer">
+          <button class="btn btn-secondary" type="button" data-dismiss="modal">Cancel</button>
+          <a class="btn btn-primary" href="login.html">Logout</a>
+        </div>
+      </div>
+    </div>
+  </div>
+
+  <!-- Bootstrap core JavaScript-->
+  <script src="vendor/jquery/jquery.min.js"></script>
+  <script src="vendor/bootstrap/js/bootstrap.bundle.min.js"></script>
+
+  <!-- Core plugin JavaScript-->
+  <script src="vendor/jquery-easing/jquery.easing.min.js"></script>
+
+  <!-- Custom scripts for all pages-->
+  <script src="js/sb-admin.min.js"></script>
+
+</body>
+
+</html>

example/example/templates/home.html

@@ -0,0 +1,19 @@
+{% extends 'base.html' %}
+{% load static %}
+{% block content %}
+      <div class="container-fluid">
+
+        <!-- Breadcrumbs-->
+        <ol class="breadcrumb">
+          <li class="breadcrumb-item">
+            <a href="index.html">Dashboard</a>
+          </li>
+          <li class="breadcrumb-item active">Blank Page</li>
+        </ol>
+
+        <!-- Page Content -->
+        <h1>Welcome {{ request.user.username }}!</h1>
+        <hr>
+
+      </div>
+      {% endblock %}

example/example/templates/login.html

@@ -0,0 +1,62 @@
+{% load static %}
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+  <meta name="description" content="">
+  <meta name="author" content="">
+
+  <title>Login</title>
+
+  <!-- Custom fonts for this template-->
+  <link href="{% static  'vendor/fontawesome-free/css/all.min.css'%}" rel="stylesheet" type="text/css">
+
+  <!-- Custom styles for this template-->
+  <link href="{% static 'css/sb-admin.css'%}" rel="stylesheet">
+
+</head>
+
+<body class="bg-dark">
+
+  <div class="container">
+    <div class="card card-login mx-auto mt-5">
+      <div class="card-header">Login</div>
+      <div class="card-body">
+          {% if invalid %}
+              <div class="alert alert-danger">Invalid Username or password</div>
+          {% endif %}
+        <form action="{% url 'login' %}" method="post">
+            {% csrf_token %}
+          <div class="form-group">
+            <div class="form-label-group">
+              <input type="text" id="inputUsername" name="username" class="form-control" placeholder="username" required="required" autofocus="autofocus">
+              <label for="inputUsername">Username</label>
+            </div>
+          </div>
+          <div class="form-group">
+            <div class="form-label-group">
+              <input type="password" id="inputPassword"  name="password" class="form-control" placeholder="Password" required="required">
+              <label for="inputPassword">Password</label>
+            </div>
+          </div>
+
+          <button class="btn btn-primary btn-block" type="submit">Login</button>
+        </form>
+      </div>
+    </div>
+  </div>
+
+  <!-- Bootstrap core JavaScript-->
+  <script src="{% static 'vendor/jquery/jquery.min.js'%}"></script>
+  <script src="{%static 'vendor/bootstrap/js/bootstrap.bundle.min.js'%}"></script>
+
+  <!-- Core plugin JavaScript-->
+  <script src="{% static 'vendor/jquery-easing/jquery.easing.min.js'%}"></script>
+
+</body>
+
+</html>

example/example/templates/logout.html

@@ -0,0 +1,43 @@
+{% load static %}
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+  <meta name="description" content="">
+  <meta name="author" content="">
+
+  <title>Login</title>
+
+  <!-- Custom fonts for this template-->
+  <link href="{% static  'vendor/fontawesome-free/css/all.min.css'%}" rel="stylesheet" type="text/css">
+
+  <!-- Custom styles for this template-->
+  <link href="{% static 'css/sb-admin.css'%}" rel="stylesheet">
+
+</head>
+
+<body class="bg-dark">
+
+  <div class="container">
+    <div class="card card-login mx-auto mt-5">
+      <div class="card-header">Logout</div>
+      <div class="card-body">
+        <p>You have logged out successfully, <a href="{% url 'login' %}">Login again</a> </p>
+      </div>
+    </div>
+  </div>
+
+  <!-- Bootstrap core JavaScript-->
+  <script src="{% static 'vendor/jquery/jquery.min.js'%}"></script>
+  <script src="{%static 'vendor/bootstrap/js/bootstrap.bundle.min.js'%}"></script>
+
+  <!-- Core plugin JavaScript-->
+  <script src="{% static 'vendor/jquery-easing/jquery.easing.min.js'%}"></script>
+
+</body>
+
+</html>

example/example/templates/mfa_auth_base.html

@@ -0,0 +1,45 @@
+{% load static %}
+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+
+  <meta charset="utf-8">
+  <meta http-equiv="X-UA-Compatible" content="IE=edge">
+  <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+  <meta name="description" content="">
+  <meta name="author" content="">
+
+  <title>Login</title>
+
+  <!-- Custom fonts for this template-->
+  <link href="{% static  'vendor/fontawesome-free/css/all.min.css'%}" rel="stylesheet" type="text/css">
+
+  <!-- Custom styles for this template-->
+  <link href="{% static 'css/sb-admin.css'%}" rel="stylesheet">
+<script src="{% static 'vendor/jquery/jquery.min.js'%}"></script>
+
+</head>
+
+<body class="bg-dark">
+
+  <div class="container">
+   <div class="card card-login mx-auto mt-5">
+      <div class="card-header">Login</div>
+      <div class="card-body">
+    {% block content %}
+  {% endblock %}
+  </div>
+   </div>
+  </div>
+
+  <!-- Bootstrap core JavaScript-->
+  <script src="{%static 'vendor/bootstrap/js/bootstrap.bundle.min.js'%}"></script>
+
+  <!-- Core plugin JavaScript-->
+  <script src="{% static 'vendor/jquery-easing/jquery.easing.min.js'%}"></script>
+    {% block head %}
+    {% endblock %}
+</body>
+
+</html>

example/example/templates/mfa_email_token_template.html

@@ -0,0 +1,2 @@
+<p>Dear {{ user.username }}</p>
+Your OTP is: <b>{{ otp }}</b>

example/example/urls.py

@@ -0,0 +1,26 @@
+"""example URL Configuration
+
+The `urlpatterns` list routes URLs to views. For more information please see:
+    https://docs.djangoproject.com/en/2.0/topics/http/urls/
+Examples:
+Function views
+    1. Add an import:  from my_app import views
+    2. Add a URL to urlpatterns:  path('', views.home, name='home')
+Class-based views
+    1. Add an import:  from other_app.views import Home
+    2. Add a URL to urlpatterns:  path('', Home.as_view(), name='home')
+Including another URLconf
+    1. Import the include() function: from django.urls import include, path
+    2. Add a URL to urlpatterns:  path('blog/', include('blog.urls'))
+"""
+from django.contrib import admin
+from django.urls import path,re_path,include
+from . import views,auth
+urlpatterns = [
+    path('admin/', admin.site.urls),
+    path('mfa/', include('mfa.urls')),
+    path('auth/login',auth.loginView,name="login"),
+    path('auth/logout',auth.logoutView,name="logout"),
+
+    re_path('^$',views.home,name='home')
+]

example/example/views.py

@@ -0,0 +1,7 @@
+from django.shortcuts import render
+from django.contrib.auth.decorators import login_required
+
+
+@login_required()
+def home(request):
+    return render(request,"home.html",{})

example/example/wsgi.py

@@ -0,0 +1,16 @@
+"""
+WSGI config for example project.
+
+It exposes the WSGI callable as a module-level variable named ``application``.
+
+For more information on this file, see
+https://docs.djangoproject.com/en/2.0/howto/deployment/wsgi/
+"""
+
+import os
+
+from django.core.wsgi import get_wsgi_application
+
+os.environ.setdefault("DJANGO_SETTINGS_MODULE", "example.settings")
+
+application = get_wsgi_application()

example/manage.py

@@ -0,0 +1,15 @@
+#!/usr/bin/env python
+import os
+import sys
+
+if __name__ == "__main__":
+    os.environ.setdefault("DJANGO_SETTINGS_MODULE", "example.settings")
+    try:
+        from django.core.management import execute_from_command_line
+    except ImportError as exc:
+        raise ImportError(
+            "Couldn't import Django. Are you sure it's installed and "
+            "available on your PYTHONPATH environment variable? Did you "
+            "forget to activate a virtual environment?"
+        ) from exc
+    execute_from_command_line(sys.argv)

example/mfa

@@ -0,0 +1 @@
+../mfa/

example/requiremnts.txt

@@ -0,0 +1,2 @@
+django==2.0
+django-sslserver

example/static/js/demo/chart-area-demo.js

@@ -0,0 +1,54 @@
+// Set new default font family and font color to mimic Bootstrap's default styling
+Chart.defaults.global.defaultFontFamily = '-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif';
+Chart.defaults.global.defaultFontColor = '#292b2c';
+
+// Area Chart Example
+var ctx = document.getElementById("myAreaChart");
+var myLineChart = new Chart(ctx, {
+  type: 'line',
+  data: {
+    labels: ["Mar 1", "Mar 2", "Mar 3", "Mar 4", "Mar 5", "Mar 6", "Mar 7", "Mar 8", "Mar 9", "Mar 10", "Mar 11", "Mar 12", "Mar 13"],
+    datasets: [{
+      label: "Sessions",
+      lineTension: 0.3,
+      backgroundColor: "rgba(2,117,216,0.2)",
+      borderColor: "rgba(2,117,216,1)",
+      pointRadius: 5,
+      pointBackgroundColor: "rgba(2,117,216,1)",
+      pointBorderColor: "rgba(255,255,255,0.8)",
+      pointHoverRadius: 5,
+      pointHoverBackgroundColor: "rgba(2,117,216,1)",
+      pointHitRadius: 50,
+      pointBorderWidth: 2,
+      data: [10000, 30162, 26263, 18394, 18287, 28682, 31274, 33259, 25849, 24159, 32651, 31984, 38451],
+    }],
+  },
+  options: {
+    scales: {
+      xAxes: [{
+        time: {
+          unit: 'date'
+        },
+        gridLines: {
+          display: false
+        },
+        ticks: {
+          maxTicksLimit: 7
+        }
+      }],
+      yAxes: [{
+        ticks: {
+          min: 0,
+          max: 40000,
+          maxTicksLimit: 5
+        },
+        gridLines: {
+          color: "rgba(0, 0, 0, .125)",
+        }
+      }],
+    },
+    legend: {
+      display: false
+    }
+  }
+});

example/static/js/demo/chart-bar-demo.js

@@ -0,0 +1,46 @@
+// Set new default font family and font color to mimic Bootstrap's default styling
+Chart.defaults.global.defaultFontFamily = '-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif';
+Chart.defaults.global.defaultFontColor = '#292b2c';
+
+// Bar Chart Example
+var ctx = document.getElementById("myBarChart");
+var myLineChart = new Chart(ctx, {
+  type: 'bar',
+  data: {
+    labels: ["January", "February", "March", "April", "May", "June"],
+    datasets: [{
+      label: "Revenue",
+      backgroundColor: "rgba(2,117,216,1)",
+      borderColor: "rgba(2,117,216,1)",
+      data: [4215, 5312, 6251, 7841, 9821, 14984],
+    }],
+  },
+  options: {
+    scales: {
+      xAxes: [{
+        time: {
+          unit: 'month'
+        },
+        gridLines: {
+          display: false
+        },
+        ticks: {
+          maxTicksLimit: 6
+        }
+      }],
+      yAxes: [{
+        ticks: {
+          min: 0,
+          max: 15000,
+          maxTicksLimit: 5
+        },
+        gridLines: {
+          display: true
+        }
+      }],
+    },
+    legend: {
+      display: false
+    }
+  }
+});

example/static/js/demo/chart-pie-demo.js

@@ -0,0 +1,16 @@
+// Set new default font family and font color to mimic Bootstrap's default styling
+Chart.defaults.global.defaultFontFamily = '-apple-system,system-ui,BlinkMacSystemFont,"Segoe UI",Roboto,"Helvetica Neue",Arial,sans-serif';
+Chart.defaults.global.defaultFontColor = '#292b2c';
+
+// Pie Chart Example
+var ctx = document.getElementById("myPieChart");
+var myPieChart = new Chart(ctx, {
+  type: 'pie',
+  data: {
+    labels: ["Blue", "Red", "Yellow", "Green"],
+    datasets: [{
+      data: [12.21, 15.58, 11.25, 8.32],
+      backgroundColor: ['#007bff', '#dc3545', '#ffc107', '#28a745'],
+    }],
+  },
+});

example/static/js/demo/datatables-demo.js

@@ -0,0 +1,4 @@
+// Call the dataTables jQuery plugin
+$(document).ready(function() {
+  $('#dataTable').DataTable();
+});

example/static/js/sb-admin.js

@@ -0,0 +1,40 @@
+(function($) {
+  "use strict"; // Start of use strict
+
+  // Toggle the side navigation
+  $("#sidebarToggle").on('click', function(e) {
+    e.preventDefault();
+    $("body").toggleClass("sidebar-toggled");
+    $(".sidebar").toggleClass("toggled");
+  });
+
+  // Prevent the content wrapper from scrolling when the fixed side navigation hovered over
+  $('body.fixed-nav .sidebar').on('mousewheel DOMMouseScroll wheel', function(e) {
+    if ($(window).width() > 768) {
+      var e0 = e.originalEvent,
+        delta = e0.wheelDelta || -e0.detail;
+      this.scrollTop += (delta < 0 ? 1 : -1) * 30;
+      e.preventDefault();
+    }
+  });
+
+  // Scroll to top button appear
+  $(document).on('scroll', function() {
+    var scrollDistance = $(this).scrollTop();
+    if (scrollDistance > 100) {
+      $('.scroll-to-top').fadeIn();
+    } else {
+      $('.scroll-to-top').fadeOut();
+    }
+  });
+
+  // Smooth scrolling using jQuery easing
+  $(document).on('click', 'a.scroll-to-top', function(event) {
+    var $anchor = $(this);
+    $('html, body').stop().animate({
+      scrollTop: ($($anchor.attr('href')).offset().top)
+    }, 1000, 'easeInOutExpo');
+    event.preventDefault();
+  });
+
+})(jQuery); // End of use strict

example/static/js/sb-admin.min.js

@@ -0,0 +1,7 @@
+/*!
+ * Start Bootstrap - SB Admin v5.1.1 (https://startbootstrap.com/template-overviews/sb-admin)
+ * Copyright 2013-2019 Start Bootstrap
+ * Licensed under MIT (https://github.com/BlackrockDigital/startbootstrap-sb-admin/blob/master/LICENSE)
+ */
+
+!function(l){"use strict";l("#sidebarToggle").on("click",function(o){o.preventDefault(),l("body").toggleClass("sidebar-toggled"),l(".sidebar").toggleClass("toggled")}),l("body.fixed-nav .sidebar").on("mousewheel DOMMouseScroll wheel",function(o){if(768<l(window).width()){var e=o.originalEvent,t=e.wheelDelta||-e.detail;this.scrollTop+=30*(t<0?1:-1),o.preventDefault()}}),l(document).on("scroll",function(){100<l(this).scrollTop()?l(".scroll-to-top").fadeIn():l(".scroll-to-top").fadeOut()}),l(document).on("click","a.scroll-to-top",function(o){var e=l(this);l("html, body").stop().animate({scrollTop:l(e.attr("href")).offset().top},1e3,"easeInOutExpo"),o.preventDefault()})}(jQuery);

example/static/mfa/css/bootstrap-toggle.min.css

@@ -0,0 +1,28 @@
+/*! ========================================================================
+ * Bootstrap Toggle: bootstrap-toggle.css v2.2.0
+ * http://www.bootstraptoggle.com
+ * ========================================================================
+ * Copyright 2014 Min Hur, The New York Times Company
+ * Licensed under MIT
+ * ======================================================================== */
+.checkbox label .toggle,.checkbox-inline .toggle{margin-left:-20px;margin-right:5px}
+.toggle{position:relative;overflow:hidden}
+.toggle input[type=checkbox]{display:none}
+.toggle-group{position:absolute;width:200%;top:0;bottom:0;left:0;transition:left .35s;-webkit-transition:left .35s;-moz-user-select:none;-webkit-user-select:none}
+.toggle.off .toggle-group{left:-100%}
+.toggle-on{position:absolute;top:0;bottom:0;left:0;right:50%;margin:0;border:0;border-radius:0}
+.toggle-off{position:absolute;top:0;bottom:0;left:50%;right:0;margin:0;border:0;border-radius:0}
+.toggle-handle{position:relative;margin:0 auto;padding-top:0;padding-bottom:0;height:100%;width:0;border-width:0 1px}
+.toggle.btn{min-width:59px;min-height:34px}
+.toggle-on.btn{padding-right:24px}
+.toggle-off.btn{padding-left:24px}
+.toggle.btn-lg{min-width:79px;min-height:45px}
+.toggle-on.btn-lg{padding-right:31px}
+.toggle-off.btn-lg{padding-left:31px}
+.toggle-handle.btn-lg{width:40px}
+.toggle.btn-sm{min-width:50px;min-height:30px}
+.toggle-on.btn-sm{padding-right:20px}
+.toggle-off.btn-sm{padding-left:20px}
+.toggle.btn-xs{min-width:35px;min-height:22px}
+.toggle-on.btn-xs{padding-right:12px}
+.toggle-off.btn-xs{padding-left:12px}

example/static/mfa/js/bootstrap-toggle.min.js

@@ -0,0 +1,9 @@
+/*! ========================================================================
+ * Bootstrap Toggle: bootstrap-toggle.js v2.2.0
+ * http://www.bootstraptoggle.com
+ * ========================================================================
+ * Copyright 2014 Min Hur, The New York Times Company
+ * Licensed under MIT
+ * ======================================================================== */
++function(a){"use strict";function b(b){return this.each(function(){var d=a(this),e=d.data("bs.toggle"),f="object"==typeof b&&b;e||d.data("bs.toggle",e=new c(this,f)),"string"==typeof b&&e[b]&&e[b]()})}var c=function(b,c){this.$element=a(b),this.options=a.extend({},this.defaults(),c),this.render()};c.VERSION="2.2.0",c.DEFAULTS={on:"On",off:"Off",onstyle:"primary",offstyle:"default",size:"normal",style:"",width:null,height:null},c.prototype.defaults=function(){return{on:this.$element.attr("data-on")||c.DEFAULTS.on,off:this.$element.attr("data-off")||c.DEFAULTS.off,onstyle:this.$element.attr("data-onstyle")||c.DEFAULTS.onstyle,offstyle:this.$element.attr("data-offstyle")||c.DEFAULTS.offstyle,size:this.$element.attr("data-size")||c.DEFAULTS.size,style:this.$element.attr("data-style")||c.DEFAULTS.style,width:this.$element.attr("data-width")||c.DEFAULTS.width,height:this.$element.attr("data-height")||c.DEFAULTS.height}},c.prototype.render=function(){this._onstyle="btn-"+this.options.onstyle,this._offstyle="btn-"+this.options.offstyle;var b="large"===this.options.size?"btn-lg":"small"===this.options.size?"btn-sm":"mini"===this.options.size?"btn-xs":"",c=a('<label class="btn">').html(this.options.on).addClass(this._onstyle+" "+b),d=a('<label class="btn">').html(this.options.off).addClass(this._offstyle+" "+b+" active"),e=a('<span class="toggle-handle btn btn-default">').addClass(b),f=a('<div class="toggle-group">').append(c,d,e),g=a('<div class="toggle btn" data-toggle="toggle">').addClass(this.$element.prop("checked")?this._onstyle:this._offstyle+" off").addClass(b).addClass(this.options.style);this.$element.wrap(g),a.extend(this,{$toggle:this.$element.parent(),$toggleOn:c,$toggleOff:d,$toggleGroup:f}),this.$toggle.append(f);var h=this.options.width||Math.max(c.outerWidth(),d.outerWidth())+e.outerWidth()/2,i=this.options.height||Math.max(c.outerHeight(),d.outerHeight());c.addClass("toggle-on"),d.addClass("toggle-off"),this.$toggle.css({width:h,height:i}),this.options.height&&(c.css("line-height",c.height()+"px"),d.css("line-height",d.height()+"px")),this.update(!0),this.trigger(!0)},c.prototype.toggle=function(){this.$element.prop("checked")?this.off():this.on()},c.prototype.on=function(a){return this.$element.prop("disabled")?!1:(this.$toggle.removeClass(this._offstyle+" off").addClass(this._onstyle),this.$element.prop("checked",!0),void(a||this.trigger()))},c.prototype.off=function(a){return this.$element.prop("disabled")?!1:(this.$toggle.removeClass(this._onstyle).addClass(this._offstyle+" off"),this.$element.prop("checked",!1),void(a||this.trigger()))},c.prototype.enable=function(){this.$toggle.removeAttr("disabled"),this.$element.prop("disabled",!1)},c.prototype.disable=function(){this.$toggle.attr("disabled","disabled"),this.$element.prop("disabled",!0)},c.prototype.update=function(a){this.$element.prop("disabled")?this.disable():this.enable(),this.$element.prop("checked")?this.on(a):this.off(a)},c.prototype.trigger=function(b){this.$element.off("change.bs.toggle"),b||this.$element.change(),this.$element.on("change.bs.toggle",a.proxy(function(){this.update()},this))},c.prototype.destroy=function(){this.$element.off("change.bs.toggle"),this.$toggleGroup.remove(),this.$element.removeData("bs.toggle"),this.$element.unwrap()};var d=a.fn.bootstrapToggle;a.fn.bootstrapToggle=b,a.fn.bootstrapToggle.Constructor=c,a.fn.toggle.noConflict=function(){return a.fn.bootstrapToggle=d,this},a(function(){a("input[type=checkbox][data-toggle^=toggle]").bootstrapToggle()}),a(document).on("click.bs.toggle","div[data-toggle^=toggle]",function(b){var c=a(this).find("input[type=checkbox]");c.bootstrapToggle("toggle"),b.preventDefault()})}(jQuery);
+//# sourceMappingURL=bootstrap-toggle.min.js.map

example/static/mfa/js/cbor.js

@@ -0,0 +1,406 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright (c) 2014-2016 Patrick Gansterer <paroga@paroga.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+(function(global, undefined) { "use strict";
+var POW_2_24 = 5.960464477539063e-8,
+    POW_2_32 = 4294967296,
+    POW_2_53 = 9007199254740992;
+
+function encode(value) {
+  var data = new ArrayBuffer(256);
+  var dataView = new DataView(data);
+  var lastLength;
+  var offset = 0;
+
+  function prepareWrite(length) {
+    var newByteLength = data.byteLength;
+    var requiredLength = offset + length;
+    while (newByteLength < requiredLength)
+      newByteLength <<= 1;
+    if (newByteLength !== data.byteLength) {
+      var oldDataView = dataView;
+      data = new ArrayBuffer(newByteLength);
+      dataView = new DataView(data);
+      var uint32count = (offset + 3) >> 2;
+      for (var i = 0; i < uint32count; ++i)
+        dataView.setUint32(i << 2, oldDataView.getUint32(i << 2));
+    }
+
+    lastLength = length;
+    return dataView;
+  }
+  function commitWrite() {
+    offset += lastLength;
+  }
+  function writeFloat64(value) {
+    commitWrite(prepareWrite(8).setFloat64(offset, value));
+  }
+  function writeUint8(value) {
+    commitWrite(prepareWrite(1).setUint8(offset, value));
+  }
+  function writeUint8Array(value) {
+    var dataView = prepareWrite(value.length);
+    for (var i = 0; i < value.length; ++i)
+      dataView.setUint8(offset + i, value[i]);
+    commitWrite();
+  }
+  function writeUint16(value) {
+    commitWrite(prepareWrite(2).setUint16(offset, value));
+  }
+  function writeUint32(value) {
+    commitWrite(prepareWrite(4).setUint32(offset, value));
+  }
+  function writeUint64(value) {
+    var low = value % POW_2_32;
+    var high = (value - low) / POW_2_32;
+    var dataView = prepareWrite(8);
+    dataView.setUint32(offset, high);
+    dataView.setUint32(offset + 4, low);
+    commitWrite();
+  }
+  function writeTypeAndLength(type, length) {
+    if (length < 24) {
+      writeUint8(type << 5 | length);
+    } else if (length < 0x100) {
+      writeUint8(type << 5 | 24);
+      writeUint8(length);
+    } else if (length < 0x10000) {
+      writeUint8(type << 5 | 25);
+      writeUint16(length);
+    } else if (length < 0x100000000) {
+      writeUint8(type << 5 | 26);
+      writeUint32(length);
+    } else {
+      writeUint8(type << 5 | 27);
+      writeUint64(length);
+    }
+  }
+
+  function encodeItem(value) {
+    var i;
+
+    if (value === false)
+      return writeUint8(0xf4);
+    if (value === true)
+      return writeUint8(0xf5);
+    if (value === null)
+      return writeUint8(0xf6);
+    if (value === undefined)
+      return writeUint8(0xf7);
+
+    switch (typeof value) {
+      case "number":
+        if (Math.floor(value) === value) {
+          if (0 <= value && value <= POW_2_53)
+            return writeTypeAndLength(0, value);
+          if (-POW_2_53 <= value && value < 0)
+            return writeTypeAndLength(1, -(value + 1));
+        }
+        writeUint8(0xfb);
+        return writeFloat64(value);
+
+      case "string":
+        var utf8data = [];
+        for (i = 0; i < value.length; ++i) {
+          var charCode = value.charCodeAt(i);
+          if (charCode < 0x80) {
+            utf8data.push(charCode);
+          } else if (charCode < 0x800) {
+            utf8data.push(0xc0 | charCode >> 6);
+            utf8data.push(0x80 | charCode & 0x3f);
+          } else if (charCode < 0xd800) {
+            utf8data.push(0xe0 | charCode >> 12);
+            utf8data.push(0x80 | (charCode >> 6)  & 0x3f);
+            utf8data.push(0x80 | charCode & 0x3f);
+          } else {
+            charCode = (charCode & 0x3ff) << 10;
+            charCode |= value.charCodeAt(++i) & 0x3ff;
+            charCode += 0x10000;
+
+            utf8data.push(0xf0 | charCode >> 18);
+            utf8data.push(0x80 | (charCode >> 12)  & 0x3f);
+            utf8data.push(0x80 | (charCode >> 6)  & 0x3f);
+            utf8data.push(0x80 | charCode & 0x3f);
+          }
+        }
+
+        writeTypeAndLength(3, utf8data.length);
+        return writeUint8Array(utf8data);
+
+      default:
+        var length;
+        if (Array.isArray(value)) {
+          length = value.length;
+          writeTypeAndLength(4, length);
+          for (i = 0; i < length; ++i)
+            encodeItem(value[i]);
+        } else if (value instanceof Uint8Array) {
+          writeTypeAndLength(2, value.length);
+          writeUint8Array(value);
+        } else {
+          var keys = Object.keys(value);
+          length = keys.length;
+          writeTypeAndLength(5, length);
+          for (i = 0; i < length; ++i) {
+            var key = keys[i];
+            encodeItem(key);
+            encodeItem(value[key]);
+          }
+        }
+    }
+  }
+
+  encodeItem(value);
+
+  if ("slice" in data)
+    return data.slice(0, offset);
+
+  var ret = new ArrayBuffer(offset);
+  var retView = new DataView(ret);
+  for (var i = 0; i < offset; ++i)
+    retView.setUint8(i, dataView.getUint8(i));
+  return ret;
+}
+
+function decode(data, tagger, simpleValue) {
+  var dataView = new DataView(data);
+  var offset = 0;
+
+  if (typeof tagger !== "function")
+    tagger = function(value) { return value; };
+  if (typeof simpleValue !== "function")
+    simpleValue = function() { return undefined; };
+
+  function commitRead(length, value) {
+    offset += length;
+    return value;
+  }
+  function readArrayBuffer(length) {
+    return commitRead(length, new Uint8Array(data, offset, length));
+  }
+  function readFloat16() {
+    var tempArrayBuffer = new ArrayBuffer(4);
+    var tempDataView = new DataView(tempArrayBuffer);
+    var value = readUint16();
+
+    var sign = value & 0x8000;
+    var exponent = value & 0x7c00;
+    var fraction = value & 0x03ff;
+
+    if (exponent === 0x7c00)
+      exponent = 0xff << 10;
+    else if (exponent !== 0)
+      exponent += (127 - 15) << 10;
+    else if (fraction !== 0)
+      return (sign ? -1 : 1) * fraction * POW_2_24;
+
+    tempDataView.setUint32(0, sign << 16 | exponent << 13 | fraction << 13);
+    return tempDataView.getFloat32(0);
+  }
+  function readFloat32() {
+    return commitRead(4, dataView.getFloat32(offset));
+  }
+  function readFloat64() {
+    return commitRead(8, dataView.getFloat64(offset));
+  }
+  function readUint8() {
+    return commitRead(1, dataView.getUint8(offset));
+  }
+  function readUint16() {
+    return commitRead(2, dataView.getUint16(offset));
+  }
+  function readUint32() {
+    return commitRead(4, dataView.getUint32(offset));
+  }
+  function readUint64() {
+    return readUint32() * POW_2_32 + readUint32();
+  }
+  function readBreak() {
+    if (dataView.getUint8(offset) !== 0xff)
+      return false;
+    offset += 1;
+    return true;
+  }
+  function readLength(additionalInformation) {
+    if (additionalInformation < 24)
+      return additionalInformation;
+    if (additionalInformation === 24)
+      return readUint8();
+    if (additionalInformation === 25)
+      return readUint16();
+    if (additionalInformation === 26)
+      return readUint32();
+    if (additionalInformation === 27)
+      return readUint64();
+    if (additionalInformation === 31)
+      return -1;
+    throw "Invalid length encoding";
+  }
+  function readIndefiniteStringLength(majorType) {
+    var initialByte = readUint8();
+    if (initialByte === 0xff)
+      return -1;
+    var length = readLength(initialByte & 0x1f);
+    if (length < 0 || (initialByte >> 5) !== majorType)
+      throw "Invalid indefinite length element";
+    return length;
+  }
+
+  function appendUtf16Data(utf16data, length) {
+    for (var i = 0; i < length; ++i) {
+      var value = readUint8();
+      if (value & 0x80) {
+        if (value < 0xe0) {
+          value = (value & 0x1f) <<  6
+                | (readUint8() & 0x3f);
+          length -= 1;
+        } else if (value < 0xf0) {
+          value = (value & 0x0f) << 12
+                | (readUint8() & 0x3f) << 6
+                | (readUint8() & 0x3f);
+          length -= 2;
+        } else {
+          value = (value & 0x0f) << 18
+                | (readUint8() & 0x3f) << 12
+                | (readUint8() & 0x3f) << 6
+                | (readUint8() & 0x3f);
+          length -= 3;
+        }
+      }
+
+      if (value < 0x10000) {
+        utf16data.push(value);
+      } else {
+        value -= 0x10000;
+        utf16data.push(0xd800 | (value >> 10));
+        utf16data.push(0xdc00 | (value & 0x3ff));
+      }
+    }
+  }
+
+  function decodeItem() {
+    var initialByte = readUint8();
+    var majorType = initialByte >> 5;
+    var additionalInformation = initialByte & 0x1f;
+    var i;
+    var length;
+
+    if (majorType === 7) {
+      switch (additionalInformation) {
+        case 25:
+          return readFloat16();
+        case 26:
+          return readFloat32();
+        case 27:
+          return readFloat64();
+      }
+    }
+
+    length = readLength(additionalInformation);
+    if (length < 0 && (majorType < 2 || 6 < majorType))
+      throw "Invalid length";
+
+    switch (majorType) {
+      case 0:
+        return length;
+      case 1:
+        return -1 - length;
+      case 2:
+        if (length < 0) {
+          var elements = [];
+          var fullArrayLength = 0;
+          while ((length = readIndefiniteStringLength(majorType)) >= 0) {
+            fullArrayLength += length;
+            elements.push(readArrayBuffer(length));
+          }
+          var fullArray = new Uint8Array(fullArrayLength);
+          var fullArrayOffset = 0;
+          for (i = 0; i < elements.length; ++i) {
+            fullArray.set(elements[i], fullArrayOffset);
+            fullArrayOffset += elements[i].length;
+          }
+          return fullArray;
+        }
+        return readArrayBuffer(length);
+      case 3:
+        var utf16data = [];
+        if (length < 0) {
+          while ((length = readIndefiniteStringLength(majorType)) >= 0)
+            appendUtf16Data(utf16data, length);
+        } else
+          appendUtf16Data(utf16data, length);
+        return String.fromCharCode.apply(null, utf16data);
+      case 4:
+        var retArray;
+        if (length < 0) {
+          retArray = [];
+          while (!readBreak())
+            retArray.push(decodeItem());
+        } else {
+          retArray = new Array(length);
+          for (i = 0; i < length; ++i)
+            retArray[i] = decodeItem();
+        }
+        return retArray;
+      case 5:
+        var retObject = {};
+        for (i = 0; i < length || length < 0 && !readBreak(); ++i) {
+          var key = decodeItem();
+          retObject[key] = decodeItem();
+        }
+        return retObject;
+      case 6:
+        return tagger(decodeItem(), length);
+      case 7:
+        switch (length) {
+          case 20:
+            return false;
+          case 21:
+            return true;
+          case 22:
+            return null;
+          case 23:
+            return undefined;
+          default:
+            return simpleValue(length);
+        }
+    }
+  }
+
+  var ret = decodeItem();
+  if (offset !== data.byteLength)
+    throw "Remaining bytes";
+  return ret;
+}
+
+var obj = { encode: encode, decode: decode };
+
+if (typeof define === "function" && define.amd)
+  define("cbor/cbor", obj);
+else if (typeof module !== "undefined" && module.exports)
+  module.exports = obj;
+else if (!global.CBOR)
+  global.CBOR = obj;
+
+})(this);

example/static/mfa/js/u2f-api.js

@@ -0,0 +1,751 @@
+//Copyright 2014-2015 Google Inc. All rights reserved.
+
+//Use of this source code is governed by a BSD-style
+//license that can be found in the LICENSE file or at
+//https://developers.google.com/open-source/licenses/bsd
+
+/**
+ * @fileoverview The U2F api.
+ */
+'use strict';
+
+
+/**
+ * Namespace for the U2F api.
+ * @type {Object}
+ */
+var u2f = u2f || {};
+
+/**
+ * FIDO U2F Javascript API Version
+ * @number
+ */
+var js_api_version;
+
+/**
+ * The U2F extension id
+ * @const {string}
+ */
+// The Chrome packaged app extension ID.
+// Uncomment this if you want to deploy a server instance that uses
+// the package Chrome app and does not require installing the U2F Chrome extension.
+ u2f.EXTENSION_ID = 'kmendfapggjehodndflmmgagdbamhnfd';
+// The U2F Chrome extension ID.
+// Uncomment this if you want to deploy a server instance that uses
+// the U2F Chrome extension to authenticate.
+// u2f.EXTENSION_ID = 'pfboblefjcgdjicmnffhdgionmgcdmne';
+
+
+/**
+ * Message types for messsages to/from the extension
+ * @const
+ * @enum {string}
+ */
+u2f.MessageTypes = {
+    'U2F_REGISTER_REQUEST': 'u2f_register_request',
+    'U2F_REGISTER_RESPONSE': 'u2f_register_response',
+    'U2F_SIGN_REQUEST': 'u2f_sign_request',
+    'U2F_SIGN_RESPONSE': 'u2f_sign_response',
+    'U2F_GET_API_VERSION_REQUEST': 'u2f_get_api_version_request',
+    'U2F_GET_API_VERSION_RESPONSE': 'u2f_get_api_version_response'
+};
+
+
+/**
+ * Response status codes
+ * @const
+ * @enum {number}
+ */
+u2f.ErrorCodes = {
+    'OK': 0,
+    'OTHER_ERROR': 1,
+    'BAD_REQUEST': 2,
+    'CONFIGURATION_UNSUPPORTED': 3,
+    'DEVICE_INELIGIBLE': 4,
+    'TIMEOUT': 5
+};
+
+
+/**
+ * A message for registration requests
+ * @typedef {{
+ *   type: u2f.MessageTypes,
+ *   appId: ?string,
+ *   timeoutSeconds: ?number,
+ *   requestId: ?number
+ * }}
+ */
+u2f.U2fRequest;
+
+
+/**
+ * A message for registration responses
+ * @typedef {{
+ *   type: u2f.MessageTypes,
+ *   responseData: (u2f.Error | u2f.RegisterResponse | u2f.SignResponse),
+ *   requestId: ?number
+ * }}
+ */
+u2f.U2fResponse;
+
+
+/**
+ * An error object for responses
+ * @typedef {{
+ *   errorCode: u2f.ErrorCodes,
+ *   errorMessage: ?string
+ * }}
+ */
+u2f.Error;
+
+/**
+ * Data object for a single sign request.
+ * @typedef {enum {BLUETOOTH_RADIO, BLUETOOTH_LOW_ENERGY, USB, NFC}}
+ */
+u2f.Transport;
+
+
+/**
+ * Data object for a single sign request.
+ * @typedef {Array<u2f.Transport>}
+ */
+u2f.Transports;
+
+/**
+ * Data object for a single sign request.
+ * @typedef {{
+ *   version: string,
+ *   challenge: string,
+ *   keyHandle: string,
+ *   appId: string
+ * }}
+ */
+u2f.SignRequest;
+
+
+/**
+ * Data object for a sign response.
+ * @typedef {{
+ *   keyHandle: string,
+ *   signatureData: string,
+ *   clientData: string
+ * }}
+ */
+u2f.SignResponse;
+
+
+/**
+ * Data object for a registration request.
+ * @typedef {{
+ *   version: string,
+ *   challenge: string
+ * }}
+ */
+u2f.RegisterRequest;
+
+
+/**
+ * Data object for a registration response.
+ * @typedef {{
+ *   version: string,
+ *   keyHandle: string,
+ *   transports: Transports,
+ *   appId: string
+ * }}
+ */
+u2f.RegisterResponse;
+
+
+/**
+ * Data object for a registered key.
+ * @typedef {{
+ *   version: string,
+ *   keyHandle: string,
+ *   transports: ?Transports,
+ *   appId: ?string
+ * }}
+ */
+u2f.RegisteredKey;
+
+
+/**
+ * Data object for a get API register response.
+ * @typedef {{
+ *   js_api_version: number
+ * }}
+ */
+u2f.GetJsApiVersionResponse;
+
+
+//Low level MessagePort API support
+
+/**
+ * Sets up a MessagePort to the U2F extension using the
+ * available mechanisms.
+ * @param {function((MessagePort|u2f.WrappedChromeRuntimePort_))} callback
+ */
+u2f.getMessagePort = function(callback) {
+  if (typeof chrome != 'undefined' && chrome.runtime) {
+    // The actual message here does not matter, but we need to get a reply
+    // for the callback to run. Thus, send an empty signature request
+    // in order to get a failure response.
+    var msg = {
+        type: u2f.MessageTypes.U2F_SIGN_REQUEST,
+        signRequests: []
+    };
+    chrome.runtime.sendMessage(u2f.EXTENSION_ID, msg, function() {
+      if (!chrome.runtime.lastError) {
+        // We are on a whitelisted origin and can talk directly
+        // with the extension.
+        u2f.getChromeRuntimePort_(callback);
+      } else {
+        // chrome.runtime was available, but we couldn't message
+        // the extension directly, use iframe
+        u2f.getIframePort_(callback);
+      }
+    });
+  } else if (u2f.isAndroidChrome_()) {
+    u2f.getAuthenticatorPort_(callback);
+  } else if (u2f.isIosChrome_()) {
+    u2f.getIosPort_(callback);
+  } else {
+    // chrome.runtime was not available at all, which is normal
+    // when this origin doesn't have access to any extensions.
+    u2f.getIframePort_(callback);
+  }
+};
+
+/**
+ * Detect chrome running on android based on the browser's useragent.
+ * @private
+ */
+u2f.isAndroidChrome_ = function() {
+  var userAgent = navigator.userAgent;
+  return userAgent.indexOf('Chrome') != -1 &&
+  userAgent.indexOf('Android') != -1;
+};
+
+/**
+ * Detect chrome running on iOS based on the browser's platform.
+ * @private
+ */
+u2f.isIosChrome_ = function() {
+  return ["iPhone", "iPad", "iPod"].indexOf(navigator.platform) > -1;
+};
+
+/**
+ * Connects directly to the extension via chrome.runtime.connect.
+ * @param {function(u2f.WrappedChromeRuntimePort_)} callback
+ * @private
+ */
+u2f.getChromeRuntimePort_ = function(callback) {
+  var port = chrome.runtime.connect(u2f.EXTENSION_ID,
+      {'includeTlsChannelId': true});
+  setTimeout(function() {
+    callback(new u2f.WrappedChromeRuntimePort_(port));
+  }, 0);
+};
+
+/**
+ * Return a 'port' abstraction to the Authenticator app.
+ * @param {function(u2f.WrappedAuthenticatorPort_)} callback
+ * @private
+ */
+u2f.getAuthenticatorPort_ = function(callback) {
+  setTimeout(function() {
+    callback(new u2f.WrappedAuthenticatorPort_());
+  }, 0);
+};
+
+/**
+ * Return a 'port' abstraction to the iOS client app.
+ * @param {function(u2f.WrappedIosPort_)} callback
+ * @private
+ */
+u2f.getIosPort_ = function(callback) {
+  setTimeout(function() {
+    callback(new u2f.WrappedIosPort_());
+  }, 0);
+};
+
+/**
+ * A wrapper for chrome.runtime.Port that is compatible with MessagePort.
+ * @param {Port} port
+ * @constructor
+ * @private
+ */
+u2f.WrappedChromeRuntimePort_ = function(port) {
+  this.port_ = port;
+};
+
+/**
+ * Format and return a sign request compliant with the JS API version supported by the extension.
+ * @param {Array<u2f.SignRequest>} signRequests
+ * @param {number} timeoutSeconds
+ * @param {number} reqId
+ * @return {Object}
+ */
+u2f.formatSignRequest_ =
+  function(appId, challenge, registeredKeys, timeoutSeconds, reqId) {
+  if (js_api_version === undefined || js_api_version < 1.1) {
+    // Adapt request to the 1.0 JS API
+    var signRequests = [];
+    for (var i = 0; i < registeredKeys.length; i++) {
+      signRequests[i] = {
+          version: registeredKeys[i].version,
+          challenge: challenge,
+          keyHandle: registeredKeys[i].keyHandle,
+          appId: appId
+      };
+    }
+    return {
+      type: u2f.MessageTypes.U2F_SIGN_REQUEST,
+      signRequests: signRequests,
+      timeoutSeconds: timeoutSeconds,
+      requestId: reqId
+    };
+  }
+  // JS 1.1 API
+  return {
+    type: u2f.MessageTypes.U2F_SIGN_REQUEST,
+    appId: appId,
+    challenge: challenge,
+    registeredKeys: registeredKeys,
+    timeoutSeconds: timeoutSeconds,
+    requestId: reqId
+  };
+};
+
+/**
+ * Format and return a register request compliant with the JS API version supported by the extension..
+ * @param {Array<u2f.SignRequest>} signRequests
+ * @param {Array<u2f.RegisterRequest>} signRequests
+ * @param {number} timeoutSeconds
+ * @param {number} reqId
+ * @return {Object}
+ */
+u2f.formatRegisterRequest_ =
+  function(appId, registeredKeys, registerRequests, timeoutSeconds, reqId) {
+  if (js_api_version === undefined || js_api_version < 1.1) {
+    // Adapt request to the 1.0 JS API
+    for (var i = 0; i < registerRequests.length; i++) {
+      registerRequests[i].appId = appId;
+    }
+    var signRequests = [];
+    for (var i = 0; i < registeredKeys.length; i++) {
+      signRequests[i] = {
+          version: registeredKeys[i].version,
+          challenge: registerRequests[0],
+          keyHandle: registeredKeys[i].keyHandle,
+          appId: appId
+      };
+    }
+    return {
+      type: u2f.MessageTypes.U2F_REGISTER_REQUEST,
+      signRequests: signRequests,
+      registerRequests: registerRequests,
+      timeoutSeconds: timeoutSeconds,
+      requestId: reqId
+    };
+  }
+  // JS 1.1 API
+  return {
+    type: u2f.MessageTypes.U2F_REGISTER_REQUEST,
+    appId: appId,
+    registerRequests: registerRequests,
+    registeredKeys: registeredKeys,
+    timeoutSeconds: timeoutSeconds,
+    requestId: reqId
+  };
+};
+
+
+/**
+ * Posts a message on the underlying channel.
+ * @param {Object} message
+ */
+u2f.WrappedChromeRuntimePort_.prototype.postMessage = function(message) {
+  this.port_.postMessage(message);
+};
+
+
+/**
+ * Emulates the HTML 5 addEventListener interface. Works only for the
+ * onmessage event, which is hooked up to the chrome.runtime.Port.onMessage.
+ * @param {string} eventName
+ * @param {function({data: Object})} handler
+ */
+u2f.WrappedChromeRuntimePort_.prototype.addEventListener =
+    function(eventName, handler) {
+  var name = eventName.toLowerCase();
+  if (name == 'message' || name == 'onmessage') {
+    this.port_.onMessage.addListener(function(message) {
+      // Emulate a minimal MessageEvent object
+      handler({'data': message});
+    });
+  } else {
+    console.error('WrappedChromeRuntimePort only supports onMessage');
+  }
+};
+
+/**
+ * Wrap the Authenticator app with a MessagePort interface.
+ * @constructor
+ * @private
+ */
+u2f.WrappedAuthenticatorPort_ = function() {
+  this.requestId_ = -1;
+  this.requestObject_ = null;
+}
+
+/**
+ * Launch the Authenticator intent.
+ * @param {Object} message
+ */
+u2f.WrappedAuthenticatorPort_.prototype.postMessage = function(message) {
+  var intentUrl =
+    u2f.WrappedAuthenticatorPort_.INTENT_URL_BASE_ +
+    ';S.request=' + encodeURIComponent(JSON.stringify(message)) +
+    ';end';
+  document.location = intentUrl;
+};
+
+/**
+ * Tells what type of port this is.
+ * @return {String} port type
+ */
+u2f.WrappedAuthenticatorPort_.prototype.getPortType = function() {
+  return "WrappedAuthenticatorPort_";
+};
+
+
+/**
+ * Emulates the HTML 5 addEventListener interface.
+ * @param {string} eventName
+ * @param {function({data: Object})} handler
+ */
+u2f.WrappedAuthenticatorPort_.prototype.addEventListener = function(eventName, handler) {
+  var name = eventName.toLowerCase();
+  if (name == 'message') {
+    var self = this;
+    /* Register a callback to that executes when
+     * chrome injects the response. */
+    window.addEventListener(
+        'message', self.onRequestUpdate_.bind(self, handler), false);
+  } else {
+    console.error('WrappedAuthenticatorPort only supports message');
+  }
+};
+
+/**
+ * Callback invoked  when a response is received from the Authenticator.
+ * @param function({data: Object}) callback
+ * @param {Object} message message Object
+ */
+u2f.WrappedAuthenticatorPort_.prototype.onRequestUpdate_ =
+    function(callback, message) {
+  var messageObject = JSON.parse(message.data);
+  var intentUrl = messageObject['intentURL'];
+
+  var errorCode = messageObject['errorCode'];
+  var responseObject = null;
+  if (messageObject.hasOwnProperty('data')) {
+    responseObject = /** @type {Object} */ (
+        JSON.parse(messageObject['data']));
+  }
+
+  callback({'data': responseObject});
+};
+
+/**
+ * Base URL for intents to Authenticator.
+ * @const
+ * @private
+ */
+u2f.WrappedAuthenticatorPort_.INTENT_URL_BASE_ =
+  'intent:#Intent;action=com.google.android.apps.authenticator.AUTHENTICATE';
+
+/**
+ * Wrap the iOS client app with a MessagePort interface.
+ * @constructor
+ * @private
+ */
+u2f.WrappedIosPort_ = function() {};
+
+/**
+ * Launch the iOS client app request
+ * @param {Object} message
+ */
+u2f.WrappedIosPort_.prototype.postMessage = function(message) {
+  var str = JSON.stringify(message);
+  var url = "u2f://auth?" + encodeURI(str);
+  location.replace(url);
+};
+
+/**
+ * Tells what type of port this is.
+ * @return {String} port type
+ */
+u2f.WrappedIosPort_.prototype.getPortType = function() {
+  return "WrappedIosPort_";
+};
+
+/**
+ * Emulates the HTML 5 addEventListener interface.
+ * @param {string} eventName
+ * @param {function({data: Object})} handler
+ */
+u2f.WrappedIosPort_.prototype.addEventListener = function(eventName, handler) {
+  var name = eventName.toLowerCase();
+  if (name !== 'message') {
+    console.error('WrappedIosPort only supports message');
+  }
+};
+
+/**
+ * Sets up an embedded trampoline iframe, sourced from the extension.
+ * @param {function(MessagePort)} callback
+ * @private
+ */
+u2f.getIframePort_ = function(callback) {
+  // Create the iframe
+  var iframeOrigin = 'chrome-extension://' + u2f.EXTENSION_ID;
+  var iframe = document.createElement('iframe');
+  iframe.src = iframeOrigin + '/u2f-comms.html';
+  iframe.setAttribute('style', 'display:none');
+  document.body.appendChild(iframe);
+
+  var channel = new MessageChannel();
+  var ready = function(message) {
+    if (message.data == 'ready') {
+      channel.port1.removeEventListener('message', ready);
+      callback(channel.port1);
+    } else {
+      console.error('First event on iframe port was not "ready"');
+    }
+  };
+  channel.port1.addEventListener('message', ready);
+  channel.port1.start();
+
+  iframe.addEventListener('load', function() {
+    // Deliver the port to the iframe and initialize
+    iframe.contentWindow.postMessage('init', iframeOrigin, [channel.port2]);
+  });
+};
+
+
+//High-level JS API
+
+/**
+ * Default extension response timeout in seconds.
+ * @const
+ */
+u2f.EXTENSION_TIMEOUT_SEC = 30;
+
+/**
+ * A singleton instance for a MessagePort to the extension.
+ * @type {MessagePort|u2f.WrappedChromeRuntimePort_}
+ * @private
+ */
+u2f.port_ = null;
+
+/**
+ * Callbacks waiting for a port
+ * @type {Array<function((MessagePort|u2f.WrappedChromeRuntimePort_))>}
+ * @private
+ */
+u2f.waitingForPort_ = [];
+
+/**
+ * A counter for requestIds.
+ * @type {number}
+ * @private
+ */
+u2f.reqCounter_ = 0;
+
+/**
+ * A map from requestIds to client callbacks
+ * @type {Object.<number,(function((u2f.Error|u2f.RegisterResponse))
+ *                       |function((u2f.Error|u2f.SignResponse)))>}
+ * @private
+ */
+u2f.callbackMap_ = {};
+
+/**
+ * Creates or retrieves the MessagePort singleton to use.
+ * @param {function((MessagePort|u2f.WrappedChromeRuntimePort_))} callback
+ * @private
+ */
+u2f.getPortSingleton_ = function(callback) {
+  if (u2f.port_) {
+    callback(u2f.port_);
+  } else {
+    if (u2f.waitingForPort_.length == 0) {
+      u2f.getMessagePort(function(port) {
+        u2f.port_ = port;
+        u2f.port_.addEventListener('message',
+            /** @type {function(Event)} */ (u2f.responseHandler_));
+
+        // Careful, here be async callbacks. Maybe.
+        while (u2f.waitingForPort_.length)
+          u2f.waitingForPort_.shift()(u2f.port_);
+      });
+    }
+    u2f.waitingForPort_.push(callback);
+  }
+};
+
+/**
+ * Handles response messages from the extension.
+ * @param {MessageEvent.<u2f.Response>} message
+ * @private
+ */
+u2f.responseHandler_ = function(message) {
+  var response = message.data;
+  var reqId = response['requestId'];
+  if (!reqId || !u2f.callbackMap_[reqId]) {
+    console.error('Unknown or missing requestId in response.');
+    return;
+  }
+  var cb = u2f.callbackMap_[reqId];
+  delete u2f.callbackMap_[reqId];
+  cb(response['responseData']);
+};
+
+/**
+ * Dispatches an array of sign requests to available U2F tokens.
+ * If the JS API version supported by the extension is unknown, it first sends a
+ * message to the extension to find out the supported API version and then it sends
+ * the sign request.
+ * @param {string=} appId
+ * @param {string=} challenge
+ * @param {Array<u2f.RegisteredKey>} registeredKeys
+ * @param {function((u2f.Error|u2f.SignResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.sign = function(appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
+  if (js_api_version === undefined) {
+    // Send a message to get the extension to JS API version, then send the actual sign request.
+    u2f.getApiVersion(
+        function (response) {
+          js_api_version = response['js_api_version'] === undefined ? 0 : response['js_api_version'];
+          console.log("Extension JS API Version: ", js_api_version);
+          u2f.sendSignRequest(appId, challenge, registeredKeys, callback, opt_timeoutSeconds);
+        });
+  } else {
+    // We know the JS API version. Send the actual sign request in the supported API version.
+    u2f.sendSignRequest(appId, challenge, registeredKeys, callback, opt_timeoutSeconds);
+  }
+};
+
+/**
+ * Dispatches an array of sign requests to available U2F tokens.
+ * @param {string=} appId
+ * @param {string=} challenge
+ * @param {Array<u2f.RegisteredKey>} registeredKeys
+ * @param {function((u2f.Error|u2f.SignResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.sendSignRequest = function(appId, challenge, registeredKeys, callback, opt_timeoutSeconds) {
+  u2f.getPortSingleton_(function(port) {
+    var reqId = ++u2f.reqCounter_;
+    u2f.callbackMap_[reqId] = callback;
+    var timeoutSeconds = (typeof opt_timeoutSeconds !== 'undefined' ?
+        opt_timeoutSeconds : u2f.EXTENSION_TIMEOUT_SEC);
+    var req = u2f.formatSignRequest_(appId, challenge, registeredKeys, timeoutSeconds, reqId);
+    port.postMessage(req);
+  });
+};
+
+/**
+ * Dispatches register requests to available U2F tokens. An array of sign
+ * requests identifies already registered tokens.
+ * If the JS API version supported by the extension is unknown, it first sends a
+ * message to the extension to find out the supported API version and then it sends
+ * the register request.
+ * @param {string=} appId
+ * @param {Array<u2f.RegisterRequest>} registerRequests
+ * @param {Array<u2f.RegisteredKey>} registeredKeys
+ * @param {function((u2f.Error|u2f.RegisterResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.register = function(appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
+  console.log("appid",appId)
+  console.log("registerRequests",registerRequests)
+  console.log("registeredKeys",registeredKeys)
+  if (js_api_version === undefined) {
+    // Send a message to get the extension to JS API version, then send the actual register request.
+    u2f.getApiVersion(
+        function (response) {
+          js_api_version = response['js_api_version'] === undefined ? 0: response['js_api_version'];
+          console.log("Extension JS API Version: ", js_api_version);
+          u2f.sendRegisterRequest(appId, registerRequests, registeredKeys,
+              callback, opt_timeoutSeconds);
+        });
+  } else {
+    // We know the JS API version. Send the actual register request in the supported API version.
+    u2f.sendRegisterRequest(appId, registerRequests, registeredKeys,
+        callback, opt_timeoutSeconds);
+  }
+};
+
+/**
+ * Dispatches register requests to available U2F tokens. An array of sign
+ * requests identifies already registered tokens.
+ * @param {string=} appId
+ * @param {Array<u2f.RegisterRequest>} registerRequests
+ * @param {Array<u2f.RegisteredKey>} registeredKeys
+ * @param {function((u2f.Error|u2f.RegisterResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.sendRegisterRequest = function(appId, registerRequests, registeredKeys, callback, opt_timeoutSeconds) {
+  u2f.getPortSingleton_(function(port) {
+    var reqId = ++u2f.reqCounter_;
+    u2f.callbackMap_[reqId] = callback;
+    var timeoutSeconds = (typeof opt_timeoutSeconds !== 'undefined' ?
+        opt_timeoutSeconds : u2f.EXTENSION_TIMEOUT_SEC);
+    var req = u2f.formatRegisterRequest_(
+        appId, registeredKeys, registerRequests, timeoutSeconds, reqId);
+    port.postMessage(req);
+  });
+};
+
+
+/**
+ * Dispatches a message to the extension to find out the supported
+ * JS API version.
+ * If the user is on a mobile phone and is thus using Google Authenticator instead
+ * of the Chrome extension, don't send the request and simply return 0.
+ * @param {function((u2f.Error|u2f.GetJsApiVersionResponse))} callback
+ * @param {number=} opt_timeoutSeconds
+ */
+u2f.getApiVersion = function(callback, opt_timeoutSeconds) {
+ u2f.getPortSingleton_(function(port) {
+   // If we are using Android Google Authenticator or iOS client app,
+   // do not fire an intent to ask which JS API version to use.
+   if (port.getPortType) {
+     var apiVersion;
+     switch (port.getPortType()) {
+       case 'WrappedIosPort_':
+       case 'WrappedAuthenticatorPort_':
+         apiVersion = 1.1;
+         break;
+
+       default:
+         apiVersion = 0;
+         break;
+     }
+     callback({ 'js_api_version': apiVersion });
+     return;
+   }
+    var reqId = ++u2f.reqCounter_;
+    u2f.callbackMap_[reqId] = callback;
+    var req = {
+      type: u2f.MessageTypes.U2F_GET_API_VERSION_REQUEST,
+      timeoutSeconds: (typeof opt_timeoutSeconds !== 'undefined' ?
+          opt_timeoutSeconds : u2f.EXTENSION_TIMEOUT_SEC),
+      requestId: reqId
+    };
+    port.postMessage(req);
+  });
+};

example/static/vendor/bootstrap/scss/_alert.scss

@@ -0,0 +1,51 @@
+//
+// Base styles
+//
+
+.alert {
+  position: relative;
+  padding: $alert-padding-y $alert-padding-x;
+  margin-bottom: $alert-margin-bottom;
+  border: $alert-border-width solid transparent;
+  @include border-radius($alert-border-radius);
+}
+
+// Headings for larger alerts
+.alert-heading {
+  // Specified to prevent conflicts of changing $headings-color
+  color: inherit;
+}
+
+// Provide class for links that match alerts
+.alert-link {
+  font-weight: $alert-link-font-weight;
+}
+
+
+// Dismissible alerts
+//
+// Expand the right padding and account for the close button's positioning.
+
+.alert-dismissible {
+  padding-right: $close-font-size + $alert-padding-x * 2;
+
+  // Adjust close link position
+  .close {
+    position: absolute;
+    top: 0;
+    right: 0;
+    padding: $alert-padding-y $alert-padding-x;
+    color: inherit;
+  }
+}
+
+
+// Alternate styles
+//
+// Generate contextual modifier classes for colorizing the alert.
+
+@each $color, $value in $theme-colors {
+  .alert-#{$color} {
+    @include alert-variant(theme-color-level($color, $alert-bg-level), theme-color-level($color, $alert-border-level), theme-color-level($color, $alert-color-level));
+  }
+}

example/static/vendor/bootstrap/scss/_badge.scss

@@ -0,0 +1,54 @@
+// Base class
+//
+// Requires one of the contextual, color modifier classes for `color` and
+// `background-color`.
+
+.badge {
+  display: inline-block;
+  padding: $badge-padding-y $badge-padding-x;
+  @include font-size($badge-font-size);
+  font-weight: $badge-font-weight;
+  line-height: 1;
+  text-align: center;
+  white-space: nowrap;
+  vertical-align: baseline;
+  @include border-radius($badge-border-radius);
+  @include transition($badge-transition);
+
+  @at-root a#{&} {
+    @include hover-focus {
+      text-decoration: none;
+    }
+  }
+
+  // Empty badges collapse automatically
+  &:empty {
+    display: none;
+  }
+}
+
+// Quick fix for badges in buttons
+.btn .badge {
+  position: relative;
+  top: -1px;
+}
+
+// Pill badges
+//
+// Make them extra rounded with a modifier to replace v3's badges.
+
+.badge-pill {
+  padding-right: $badge-pill-padding-x;
+  padding-left: $badge-pill-padding-x;
+  @include border-radius($badge-pill-border-radius);
+}
+
+// Colors
+//
+// Contextual variations (linked badges get darker on :hover).
+
+@each $color, $value in $theme-colors {
+  .badge-#{$color} {
+    @include badge-variant($value);
+  }
+}

example/static/vendor/bootstrap/scss/_breadcrumb.scss

@@ -0,0 +1,41 @@
+.breadcrumb {
+  display: flex;
+  flex-wrap: wrap;
+  padding: $breadcrumb-padding-y $breadcrumb-padding-x;
+  margin-bottom: $breadcrumb-margin-bottom;
+  list-style: none;
+  background-color: $breadcrumb-bg;
+  @include border-radius($breadcrumb-border-radius);
+}
+
+.breadcrumb-item {
+  // The separator between breadcrumbs (by default, a forward-slash: "/")
+  + .breadcrumb-item {
+    padding-left: $breadcrumb-item-padding;
+
+    &::before {
+      display: inline-block; // Suppress underlining of the separator in modern browsers
+      padding-right: $breadcrumb-item-padding;
+      color: $breadcrumb-divider-color;
+      content: $breadcrumb-divider;
+    }
+  }
+
+  // IE9-11 hack to properly handle hyperlink underlines for breadcrumbs built
+  // without `<ul>`s. The `::before` pseudo-element generates an element
+  // *within* the .breadcrumb-item and thereby inherits the `text-decoration`.
+  //
+  // To trick IE into suppressing the underline, we give the pseudo-element an
+  // underline and then immediately remove it.
+  + .breadcrumb-item:hover::before {
+    text-decoration: underline;
+  }
+  // stylelint-disable-next-line no-duplicate-selectors
+  + .breadcrumb-item:hover::before {
+    text-decoration: none;
+  }
+
+  &.active {
+    color: $breadcrumb-active-color;
+  }
+}

example/static/vendor/bootstrap/scss/_button-group.scss

@@ -0,0 +1,163 @@
+// stylelint-disable selector-no-qualifying-type
+
+// Make the div behave like a button
+.btn-group,
+.btn-group-vertical {
+  position: relative;
+  display: inline-flex;
+  vertical-align: middle; // match .btn alignment given font-size hack above
+
+  > .btn {
+    position: relative;
+    flex: 1 1 auto;
+
+    // Bring the hover, focused, and "active" buttons to the front to overlay
+    // the borders properly
+    @include hover {
+      z-index: 1;
+    }
+    &:focus,
+    &:active,
+    &.active {
+      z-index: 1;
+    }
+  }
+}
+
+// Optional: Group multiple button groups together for a toolbar
+.btn-toolbar {
+  display: flex;
+  flex-wrap: wrap;
+  justify-content: flex-start;
+
+  .input-group {
+    width: auto;
+  }
+}
+
+.btn-group {
+  // Prevent double borders when buttons are next to each other
+  > .btn:not(:first-child),
+  > .btn-group:not(:first-child) {
+    margin-left: -$btn-border-width;
+  }
+
+  // Reset rounded corners
+  > .btn:not(:last-child):not(.dropdown-toggle),
+  > .btn-group:not(:last-child) > .btn {
+    @include border-right-radius(0);
+  }
+
+  > .btn:not(:first-child),
+  > .btn-group:not(:first-child) > .btn {
+    @include border-left-radius(0);
+  }
+}
+
+// Sizing
+//
+// Remix the default button sizing classes into new ones for easier manipulation.
+
+.btn-group-sm > .btn { @extend .btn-sm; }
+.btn-group-lg > .btn { @extend .btn-lg; }
+
+
+//
+// Split button dropdowns
+//
+
+.dropdown-toggle-split {
+  padding-right: $btn-padding-x * .75;
+  padding-left: $btn-padding-x * .75;
+
+  &::after,
+  .dropup &::after,
+  .dropright &::after {
+    margin-left: 0;
+  }
+
+  .dropleft &::before {
+    margin-right: 0;
+  }
+}
+
+.btn-sm + .dropdown-toggle-split {
+  padding-right: $btn-padding-x-sm * .75;
+  padding-left: $btn-padding-x-sm * .75;
+}
+
+.btn-lg + .dropdown-toggle-split {
+  padding-right: $btn-padding-x-lg * .75;
+  padding-left: $btn-padding-x-lg * .75;
+}
+
+
+// The clickable button for toggling the menu
+// Set the same inset shadow as the :active state
+.btn-group.show .dropdown-toggle {
+  @include box-shadow($btn-active-box-shadow);
+
+  // Show no shadow for `.btn-link` since it has no other button styles.
+  &.btn-link {
+    @include box-shadow(none);
+  }
+}
+
+
+//
+// Vertical button groups
+//
+
+.btn-group-vertical {
+  flex-direction: column;
+  align-items: flex-start;
+  justify-content: center;
+
+  > .btn,
+  > .btn-group {
+    width: 100%;
+  }
+
+  > .btn:not(:first-child),
+  > .btn-group:not(:first-child) {
+    margin-top: -$btn-border-width;
+  }
+
+  // Reset rounded corners
+  > .btn:not(:last-child):not(.dropdown-toggle),
+  > .btn-group:not(:last-child) > .btn {
+    @include border-bottom-radius(0);
+  }
+
+  > .btn:not(:first-child),
+  > .btn-group:not(:first-child) > .btn {
+    @include border-top-radius(0);
+  }
+}
+
+
+// Checkbox and radio options
+//
+// In order to support the browser's form validation feedback, powered by the
+// `required` attribute, we have to "hide" the inputs via `clip`. We cannot use
+// `display: none;` or `visibility: hidden;` as that also hides the popover.
+// Simply visually hiding the inputs via `opacity` would leave them clickable in
+// certain cases which is prevented by using `clip` and `pointer-events`.
+// This way, we ensure a DOM element is visible to position the popover from.
+//
+// See https://github.com/twbs/bootstrap/pull/12794 and
+// https://github.com/twbs/bootstrap/pull/14559 for more information.
+
+.btn-group-toggle {
+  > .btn,
+  > .btn-group > .btn {
+    margin-bottom: 0; // Override default `<label>` value
+
+    input[type="radio"],
+    input[type="checkbox"] {
+      position: absolute;
+      clip: rect(0, 0, 0, 0);
+      pointer-events: none;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_buttons.scss

@@ -0,0 +1,137 @@
+// stylelint-disable selector-no-qualifying-type
+
+//
+// Base styles
+//
+
+.btn {
+  display: inline-block;
+  font-family: $btn-font-family;
+  font-weight: $btn-font-weight;
+  color: $body-color;
+  text-align: center;
+  vertical-align: middle;
+  user-select: none;
+  background-color: transparent;
+  border: $btn-border-width solid transparent;
+  @include button-size($btn-padding-y, $btn-padding-x, $btn-font-size, $btn-line-height, $btn-border-radius);
+  @include transition($btn-transition);
+
+  @include hover {
+    color: $body-color;
+    text-decoration: none;
+  }
+
+  &:focus,
+  &.focus {
+    outline: 0;
+    box-shadow: $btn-focus-box-shadow;
+  }
+
+  // Disabled comes first so active can properly restyle
+  &.disabled,
+  &:disabled {
+    opacity: $btn-disabled-opacity;
+    @include box-shadow(none);
+  }
+
+  &:not(:disabled):not(.disabled):active,
+  &:not(:disabled):not(.disabled).active {
+    @include box-shadow($btn-active-box-shadow);
+
+    &:focus {
+      @include box-shadow($btn-focus-box-shadow, $btn-active-box-shadow);
+    }
+  }
+}
+
+// Future-proof disabling of clicks on `<a>` elements
+a.btn.disabled,
+fieldset:disabled a.btn {
+  pointer-events: none;
+}
+
+
+//
+// Alternate buttons
+//
+
+@each $color, $value in $theme-colors {
+  .btn-#{$color} {
+    @include button-variant($value, $value);
+  }
+}
+
+@each $color, $value in $theme-colors {
+  .btn-outline-#{$color} {
+    @include button-outline-variant($value);
+  }
+}
+
+
+//
+// Link buttons
+//
+
+// Make a button look and behave like a link
+.btn-link {
+  font-weight: $font-weight-normal;
+  color: $link-color;
+  text-decoration: $link-decoration;
+
+  @include hover {
+    color: $link-hover-color;
+    text-decoration: $link-hover-decoration;
+  }
+
+  &:focus,
+  &.focus {
+    text-decoration: $link-hover-decoration;
+    box-shadow: none;
+  }
+
+  &:disabled,
+  &.disabled {
+    color: $btn-link-disabled-color;
+    pointer-events: none;
+  }
+
+  // No need for an active state here
+}
+
+
+//
+// Button Sizes
+//
+
+.btn-lg {
+  @include button-size($btn-padding-y-lg, $btn-padding-x-lg, $btn-font-size-lg, $btn-line-height-lg, $btn-border-radius-lg);
+}
+
+.btn-sm {
+  @include button-size($btn-padding-y-sm, $btn-padding-x-sm, $btn-font-size-sm, $btn-line-height-sm, $btn-border-radius-sm);
+}
+
+
+//
+// Block button
+//
+
+.btn-block {
+  display: block;
+  width: 100%;
+
+  // Vertically space out multiple block buttons
+  + .btn-block {
+    margin-top: $btn-block-spacing-y;
+  }
+}
+
+// Specificity overrides
+input[type="submit"],
+input[type="reset"],
+input[type="button"] {
+  &.btn-block {
+    width: 100%;
+  }
+}

example/static/vendor/bootstrap/scss/_card.scss

@@ -0,0 +1,289 @@
+//
+// Base styles
+//
+
+.card {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  min-width: 0; // See https://github.com/twbs/bootstrap/pull/22740#issuecomment-305868106
+  word-wrap: break-word;
+  background-color: $card-bg;
+  background-clip: border-box;
+  border: $card-border-width solid $card-border-color;
+  @include border-radius($card-border-radius);
+
+  > hr {
+    margin-right: 0;
+    margin-left: 0;
+  }
+
+  > .list-group:first-child {
+    .list-group-item:first-child {
+      @include border-top-radius($card-border-radius);
+    }
+  }
+
+  > .list-group:last-child {
+    .list-group-item:last-child {
+      @include border-bottom-radius($card-border-radius);
+    }
+  }
+}
+
+.card-body {
+  // Enable `flex-grow: 1` for decks and groups so that card blocks take up
+  // as much space as possible, ensuring footers are aligned to the bottom.
+  flex: 1 1 auto;
+  padding: $card-spacer-x;
+  color: $card-color;
+}
+
+.card-title {
+  margin-bottom: $card-spacer-y;
+}
+
+.card-subtitle {
+  margin-top: -$card-spacer-y / 2;
+  margin-bottom: 0;
+}
+
+.card-text:last-child {
+  margin-bottom: 0;
+}
+
+.card-link {
+  @include hover {
+    text-decoration: none;
+  }
+
+  + .card-link {
+    margin-left: $card-spacer-x;
+  }
+}
+
+//
+// Optional textual caps
+//
+
+.card-header {
+  padding: $card-spacer-y $card-spacer-x;
+  margin-bottom: 0; // Removes the default margin-bottom of <hN>
+  color: $card-cap-color;
+  background-color: $card-cap-bg;
+  border-bottom: $card-border-width solid $card-border-color;
+
+  &:first-child {
+    @include border-radius($card-inner-border-radius $card-inner-border-radius 0 0);
+  }
+
+  + .list-group {
+    .list-group-item:first-child {
+      border-top: 0;
+    }
+  }
+}
+
+.card-footer {
+  padding: $card-spacer-y $card-spacer-x;
+  background-color: $card-cap-bg;
+  border-top: $card-border-width solid $card-border-color;
+
+  &:last-child {
+    @include border-radius(0 0 $card-inner-border-radius $card-inner-border-radius);
+  }
+}
+
+
+//
+// Header navs
+//
+
+.card-header-tabs {
+  margin-right: -$card-spacer-x / 2;
+  margin-bottom: -$card-spacer-y;
+  margin-left: -$card-spacer-x / 2;
+  border-bottom: 0;
+}
+
+.card-header-pills {
+  margin-right: -$card-spacer-x / 2;
+  margin-left: -$card-spacer-x / 2;
+}
+
+// Card image
+.card-img-overlay {
+  position: absolute;
+  top: 0;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  padding: $card-img-overlay-padding;
+}
+
+.card-img {
+  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
+  @include border-radius($card-inner-border-radius);
+}
+
+// Card image caps
+.card-img-top {
+  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
+  @include border-top-radius($card-inner-border-radius);
+}
+
+.card-img-bottom {
+  width: 100%; // Required because we use flexbox and this inherently applies align-self: stretch
+  @include border-bottom-radius($card-inner-border-radius);
+}
+
+
+// Card deck
+
+.card-deck {
+  display: flex;
+  flex-direction: column;
+
+  .card {
+    margin-bottom: $card-deck-margin;
+  }
+
+  @include media-breakpoint-up(sm) {
+    flex-flow: row wrap;
+    margin-right: -$card-deck-margin;
+    margin-left: -$card-deck-margin;
+
+    .card {
+      display: flex;
+      // Flexbugs #4: https://github.com/philipwalton/flexbugs#flexbug-4
+      flex: 1 0 0%;
+      flex-direction: column;
+      margin-right: $card-deck-margin;
+      margin-bottom: 0; // Override the default
+      margin-left: $card-deck-margin;
+    }
+  }
+}
+
+
+//
+// Card groups
+//
+
+.card-group {
+  display: flex;
+  flex-direction: column;
+
+  // The child selector allows nested `.card` within `.card-group`
+  // to display properly.
+  > .card {
+    margin-bottom: $card-group-margin;
+  }
+
+  @include media-breakpoint-up(sm) {
+    flex-flow: row wrap;
+    // The child selector allows nested `.card` within `.card-group`
+    // to display properly.
+    > .card {
+      // Flexbugs #4: https://github.com/philipwalton/flexbugs#flexbug-4
+      flex: 1 0 0%;
+      margin-bottom: 0;
+
+      + .card {
+        margin-left: 0;
+        border-left: 0;
+      }
+
+      // Handle rounded corners
+      @if $enable-rounded {
+        &:not(:last-child) {
+          @include border-right-radius(0);
+
+          .card-img-top,
+          .card-header {
+            // stylelint-disable-next-line property-blacklist
+            border-top-right-radius: 0;
+          }
+          .card-img-bottom,
+          .card-footer {
+            // stylelint-disable-next-line property-blacklist
+            border-bottom-right-radius: 0;
+          }
+        }
+
+        &:not(:first-child) {
+          @include border-left-radius(0);
+
+          .card-img-top,
+          .card-header {
+            // stylelint-disable-next-line property-blacklist
+            border-top-left-radius: 0;
+          }
+          .card-img-bottom,
+          .card-footer {
+            // stylelint-disable-next-line property-blacklist
+            border-bottom-left-radius: 0;
+          }
+        }
+      }
+    }
+  }
+}
+
+
+//
+// Columns
+//
+
+.card-columns {
+  .card {
+    margin-bottom: $card-columns-margin;
+  }
+
+  @include media-breakpoint-up(sm) {
+    column-count: $card-columns-count;
+    column-gap: $card-columns-gap;
+    orphans: 1;
+    widows: 1;
+
+    .card {
+      display: inline-block; // Don't let them vertically span multiple columns
+      width: 100%; // Don't let their width change
+    }
+  }
+}
+
+
+//
+// Accordion
+//
+
+.accordion {
+  > .card {
+    overflow: hidden;
+
+    &:not(:first-of-type) {
+      .card-header:first-child {
+        @include border-radius(0);
+      }
+
+      &:not(:last-of-type) {
+        border-bottom: 0;
+        @include border-radius(0);
+      }
+    }
+
+    &:first-of-type {
+      border-bottom: 0;
+      @include border-bottom-radius(0);
+    }
+
+    &:last-of-type {
+      @include border-top-radius(0);
+    }
+
+    .card-header {
+      margin-bottom: -$card-border-width;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_carousel.scss

@@ -0,0 +1,197 @@
+// Notes on the classes:
+//
+// 1. .carousel.pointer-event should ideally be pan-y (to allow for users to scroll vertically)
+//    even when their scroll action started on a carousel, but for compatibility (with Firefox)
+//    we're preventing all actions instead
+// 2. The .carousel-item-left and .carousel-item-right is used to indicate where
+//    the active slide is heading.
+// 3. .active.carousel-item is the current slide.
+// 4. .active.carousel-item-left and .active.carousel-item-right is the current
+//    slide in its in-transition state. Only one of these occurs at a time.
+// 5. .carousel-item-next.carousel-item-left and .carousel-item-prev.carousel-item-right
+//    is the upcoming slide in transition.
+
+.carousel {
+  position: relative;
+}
+
+.carousel.pointer-event {
+  touch-action: pan-y;
+}
+
+.carousel-inner {
+  position: relative;
+  width: 100%;
+  overflow: hidden;
+  @include clearfix();
+}
+
+.carousel-item {
+  position: relative;
+  display: none;
+  float: left;
+  width: 100%;
+  margin-right: -100%;
+  backface-visibility: hidden;
+  @include transition($carousel-transition);
+}
+
+.carousel-item.active,
+.carousel-item-next,
+.carousel-item-prev {
+  display: block;
+}
+
+.carousel-item-next:not(.carousel-item-left),
+.active.carousel-item-right {
+  transform: translateX(100%);
+}
+
+.carousel-item-prev:not(.carousel-item-right),
+.active.carousel-item-left {
+  transform: translateX(-100%);
+}
+
+
+//
+// Alternate transitions
+//
+
+.carousel-fade {
+  .carousel-item {
+    opacity: 0;
+    transition-property: opacity;
+    transform: none;
+  }
+
+  .carousel-item.active,
+  .carousel-item-next.carousel-item-left,
+  .carousel-item-prev.carousel-item-right {
+    z-index: 1;
+    opacity: 1;
+  }
+
+  .active.carousel-item-left,
+  .active.carousel-item-right {
+    z-index: 0;
+    opacity: 0;
+    @include transition(0s $carousel-transition-duration opacity);
+  }
+}
+
+
+//
+// Left/right controls for nav
+//
+
+.carousel-control-prev,
+.carousel-control-next {
+  position: absolute;
+  top: 0;
+  bottom: 0;
+  z-index: 1;
+  // Use flex for alignment (1-3)
+  display: flex; // 1. allow flex styles
+  align-items: center; // 2. vertically center contents
+  justify-content: center; // 3. horizontally center contents
+  width: $carousel-control-width;
+  color: $carousel-control-color;
+  text-align: center;
+  opacity: $carousel-control-opacity;
+  @include transition($carousel-control-transition);
+
+  // Hover/focus state
+  @include hover-focus {
+    color: $carousel-control-color;
+    text-decoration: none;
+    outline: 0;
+    opacity: $carousel-control-hover-opacity;
+  }
+}
+.carousel-control-prev {
+  left: 0;
+  @if $enable-gradients {
+    background: linear-gradient(90deg, rgba($black, .25), rgba($black, .001));
+  }
+}
+.carousel-control-next {
+  right: 0;
+  @if $enable-gradients {
+    background: linear-gradient(270deg, rgba($black, .25), rgba($black, .001));
+  }
+}
+
+// Icons for within
+.carousel-control-prev-icon,
+.carousel-control-next-icon {
+  display: inline-block;
+  width: $carousel-control-icon-width;
+  height: $carousel-control-icon-width;
+  background: no-repeat 50% / 100% 100%;
+}
+.carousel-control-prev-icon {
+  background-image: $carousel-control-prev-icon-bg;
+}
+.carousel-control-next-icon {
+  background-image: $carousel-control-next-icon-bg;
+}
+
+
+// Optional indicator pips
+//
+// Add an ordered list with the following class and add a list item for each
+// slide your carousel holds.
+
+.carousel-indicators {
+  position: absolute;
+  right: 0;
+  bottom: 0;
+  left: 0;
+  z-index: 15;
+  display: flex;
+  justify-content: center;
+  padding-left: 0; // override <ol> default
+  // Use the .carousel-control's width as margin so we don't overlay those
+  margin-right: $carousel-control-width;
+  margin-left: $carousel-control-width;
+  list-style: none;
+
+  li {
+    box-sizing: content-box;
+    flex: 0 1 auto;
+    width: $carousel-indicator-width;
+    height: $carousel-indicator-height;
+    margin-right: $carousel-indicator-spacer;
+    margin-left: $carousel-indicator-spacer;
+    text-indent: -999px;
+    cursor: pointer;
+    background-color: $carousel-indicator-active-bg;
+    background-clip: padding-box;
+    // Use transparent borders to increase the hit area by 10px on top and bottom.
+    border-top: $carousel-indicator-hit-area-height solid transparent;
+    border-bottom: $carousel-indicator-hit-area-height solid transparent;
+    opacity: .5;
+    @include transition($carousel-indicator-transition);
+  }
+
+  .active {
+    opacity: 1;
+  }
+}
+
+
+// Optional captions
+//
+//
+
+.carousel-caption {
+  position: absolute;
+  right: (100% - $carousel-caption-width) / 2;
+  bottom: 20px;
+  left: (100% - $carousel-caption-width) / 2;
+  z-index: 10;
+  padding-top: 20px;
+  padding-bottom: 20px;
+  color: $carousel-caption-color;
+  text-align: center;
+}

example/static/vendor/bootstrap/scss/_close.scss

@@ -0,0 +1,41 @@
+.close {
+  float: right;
+  @include font-size($close-font-size);
+  font-weight: $close-font-weight;
+  line-height: 1;
+  color: $close-color;
+  text-shadow: $close-text-shadow;
+  opacity: .5;
+
+  // Override <a>'s hover style
+  @include hover {
+    color: $close-color;
+    text-decoration: none;
+  }
+
+  &:not(:disabled):not(.disabled) {
+    @include hover-focus {
+      opacity: .75;
+    }
+  }
+}
+
+// Additional properties for button version
+// iOS requires the button element instead of an anchor tag.
+// If you want the anchor version, it requires `href="#"`.
+// See https://developer.mozilla.org/en-US/docs/Web/Events/click#Safari_Mobile
+
+// stylelint-disable-next-line selector-no-qualifying-type
+button.close {
+  padding: 0;
+  background-color: transparent;
+  border: 0;
+  appearance: none;
+}
+
+// Future-proof disabling of clicks on `<a>` elements
+
+// stylelint-disable-next-line selector-no-qualifying-type
+a.close.disabled {
+  pointer-events: none;
+}

example/static/vendor/bootstrap/scss/_code.scss

@@ -0,0 +1,48 @@
+// Inline code
+code {
+  @include font-size($code-font-size);
+  color: $code-color;
+  word-break: break-word;
+
+  // Streamline the style when inside anchors to avoid broken underline and more
+  a > & {
+    color: inherit;
+  }
+}
+
+// User input typically entered via keyboard
+kbd {
+  padding: $kbd-padding-y $kbd-padding-x;
+  @include font-size($kbd-font-size);
+  color: $kbd-color;
+  background-color: $kbd-bg;
+  @include border-radius($border-radius-sm);
+  @include box-shadow($kbd-box-shadow);
+
+  kbd {
+    padding: 0;
+    @include font-size(100%);
+    font-weight: $nested-kbd-font-weight;
+    @include box-shadow(none);
+  }
+}
+
+// Blocks of code
+pre {
+  display: block;
+  @include font-size($code-font-size);
+  color: $pre-color;
+
+  // Account for some code outputs that place code tags in pre tags
+  code {
+    @include font-size(inherit);
+    color: inherit;
+    word-break: normal;
+  }
+}
+
+// Enable scrollable blocks of code
+.pre-scrollable {
+  max-height: $pre-scrollable-max-height;
+  overflow-y: scroll;
+}

example/static/vendor/bootstrap/scss/_custom-forms.scss

@@ -0,0 +1,507 @@
+// Embedded icons from Open Iconic.
+// Released under MIT and copyright 2014 Waybury.
+// https://useiconic.com/open
+
+
+// Checkboxes and radios
+//
+// Base class takes care of all the key behavioral aspects.
+
+.custom-control {
+  position: relative;
+  display: block;
+  min-height: $font-size-base * $line-height-base;
+  padding-left: $custom-control-gutter + $custom-control-indicator-size;
+}
+
+.custom-control-inline {
+  display: inline-flex;
+  margin-right: $custom-control-spacer-x;
+}
+
+.custom-control-input {
+  position: absolute;
+  z-index: -1; // Put the input behind the label so it doesn't overlay text
+  opacity: 0;
+
+  &:checked ~ .custom-control-label::before {
+    color: $custom-control-indicator-checked-color;
+    border-color: $custom-control-indicator-checked-border-color;
+    @include gradient-bg($custom-control-indicator-checked-bg);
+    @include box-shadow($custom-control-indicator-checked-box-shadow);
+  }
+
+  &:focus ~ .custom-control-label::before {
+    // the mixin is not used here to make sure there is feedback
+    @if $enable-shadows {
+      box-shadow: $input-box-shadow, $input-focus-box-shadow;
+    } @else {
+      box-shadow: $custom-control-indicator-focus-box-shadow;
+    }
+  }
+
+  &:focus:not(:checked) ~ .custom-control-label::before {
+    border-color: $custom-control-indicator-focus-border-color;
+  }
+
+  &:not(:disabled):active ~ .custom-control-label::before {
+    color: $custom-control-indicator-active-color;
+    background-color: $custom-control-indicator-active-bg;
+    border-color: $custom-control-indicator-active-border-color;
+    @include box-shadow($custom-control-indicator-active-box-shadow);
+  }
+
+  &:disabled {
+    ~ .custom-control-label {
+      color: $custom-control-label-disabled-color;
+
+      &::before {
+        background-color: $custom-control-indicator-disabled-bg;
+      }
+    }
+  }
+}
+
+// Custom control indicators
+//
+// Build the custom controls out of pseudo-elements.
+
+.custom-control-label {
+  position: relative;
+  margin-bottom: 0;
+  vertical-align: top;
+
+  // Background-color and (when enabled) gradient
+  &::before {
+    position: absolute;
+    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) / 2;
+    left: -($custom-control-gutter + $custom-control-indicator-size);
+    display: block;
+    width: $custom-control-indicator-size;
+    height: $custom-control-indicator-size;
+    pointer-events: none;
+    content: "";
+    background-color: $custom-control-indicator-bg;
+    border: $custom-control-indicator-border-color solid $custom-control-indicator-border-width;
+    @include box-shadow($custom-control-indicator-box-shadow);
+  }
+
+  // Foreground (icon)
+  &::after {
+    position: absolute;
+    top: ($font-size-base * $line-height-base - $custom-control-indicator-size) / 2;
+    left: -($custom-control-gutter + $custom-control-indicator-size);
+    display: block;
+    width: $custom-control-indicator-size;
+    height: $custom-control-indicator-size;
+    content: "";
+    background: no-repeat 50% / #{$custom-control-indicator-bg-size};
+  }
+}
+
+
+// Checkboxes
+//
+// Tweak just a few things for checkboxes.
+
+.custom-checkbox {
+  .custom-control-label::before {
+    @include border-radius($custom-checkbox-indicator-border-radius);
+  }
+
+  .custom-control-input:checked ~ .custom-control-label {
+    &::after {
+      background-image: $custom-checkbox-indicator-icon-checked;
+    }
+  }
+
+  .custom-control-input:indeterminate ~ .custom-control-label {
+    &::before {
+      border-color: $custom-checkbox-indicator-indeterminate-border-color;
+      @include gradient-bg($custom-checkbox-indicator-indeterminate-bg);
+      @include box-shadow($custom-checkbox-indicator-indeterminate-box-shadow);
+    }
+    &::after {
+      background-image: $custom-checkbox-indicator-icon-indeterminate;
+    }
+  }
+
+  .custom-control-input:disabled {
+    &:checked ~ .custom-control-label::before {
+      background-color: $custom-control-indicator-checked-disabled-bg;
+    }
+    &:indeterminate ~ .custom-control-label::before {
+      background-color: $custom-control-indicator-checked-disabled-bg;
+    }
+  }
+}
+
+// Radios
+//
+// Tweak just a few things for radios.
+
+.custom-radio {
+  .custom-control-label::before {
+    // stylelint-disable-next-line property-blacklist
+    border-radius: $custom-radio-indicator-border-radius;
+  }
+
+  .custom-control-input:checked ~ .custom-control-label {
+    &::after {
+      background-image: $custom-radio-indicator-icon-checked;
+    }
+  }
+
+  .custom-control-input:disabled {
+    &:checked ~ .custom-control-label::before {
+      background-color: $custom-control-indicator-checked-disabled-bg;
+    }
+  }
+}
+
+
+// switches
+//
+// Tweak a few things for switches
+
+.custom-switch {
+  padding-left: $custom-switch-width + $custom-control-gutter;
+
+  .custom-control-label {
+    &::before {
+      left: -($custom-switch-width + $custom-control-gutter);
+      width: $custom-switch-width;
+      pointer-events: all;
+      // stylelint-disable-next-line property-blacklist
+      border-radius: $custom-switch-indicator-border-radius;
+    }
+
+    &::after {
+      top: calc(#{(($font-size-base * $line-height-base - $custom-control-indicator-size) / 2)} + #{$custom-control-indicator-border-width * 2});
+      left: calc(#{-($custom-switch-width + $custom-control-gutter)} + #{$custom-control-indicator-border-width * 2});
+      width: $custom-switch-indicator-size;
+      height: $custom-switch-indicator-size;
+      background-color: $custom-control-indicator-border-color;
+      // stylelint-disable-next-line property-blacklist
+      border-radius: $custom-switch-indicator-border-radius;
+      @include transition(transform .15s ease-in-out, $custom-forms-transition);
+    }
+  }
+
+  .custom-control-input:checked ~ .custom-control-label {
+    &::after {
+      background-color: $custom-control-indicator-bg;
+      transform: translateX($custom-switch-width - $custom-control-indicator-size);
+    }
+  }
+
+  .custom-control-input:disabled {
+    &:checked ~ .custom-control-label::before {
+      background-color: $custom-control-indicator-checked-disabled-bg;
+    }
+  }
+}
+
+
+// Select
+//
+// Replaces the browser default select with a custom one, mostly pulled from
+// https://primer.github.io/.
+//
+
+.custom-select {
+  display: inline-block;
+  width: 100%;
+  height: $custom-select-height;
+  padding: $custom-select-padding-y ($custom-select-padding-x + $custom-select-indicator-padding) $custom-select-padding-y $custom-select-padding-x;
+  font-family: $custom-select-font-family;
+  @include font-size($custom-select-font-size);
+  font-weight: $custom-select-font-weight;
+  line-height: $custom-select-line-height;
+  color: $custom-select-color;
+  vertical-align: middle;
+  background: $custom-select-background;
+  background-color: $custom-select-bg;
+  border: $custom-select-border-width solid $custom-select-border-color;
+  @include border-radius($custom-select-border-radius, 0);
+  @include box-shadow($custom-select-box-shadow);
+  appearance: none;
+
+  &:focus {
+    border-color: $custom-select-focus-border-color;
+    outline: 0;
+    @if $enable-shadows {
+      box-shadow: $custom-select-box-shadow, $custom-select-focus-box-shadow;
+    } @else {
+      box-shadow: $custom-select-focus-box-shadow;
+    }
+
+    &::-ms-value {
+      // For visual consistency with other platforms/browsers,
+      // suppress the default white text on blue background highlight given to
+      // the selected option text when the (still closed) <select> receives focus
+      // in IE and (under certain conditions) Edge.
+      // See https://github.com/twbs/bootstrap/issues/19398.
+      color: $input-color;
+      background-color: $input-bg;
+    }
+  }
+
+  &[multiple],
+  &[size]:not([size="1"]) {
+    height: auto;
+    padding-right: $custom-select-padding-x;
+    background-image: none;
+  }
+
+  &:disabled {
+    color: $custom-select-disabled-color;
+    background-color: $custom-select-disabled-bg;
+  }
+
+  // Hides the default caret in IE11
+  &::-ms-expand {
+    display: none;
+  }
+}
+
+.custom-select-sm {
+  height: $custom-select-height-sm;
+  padding-top: $custom-select-padding-y-sm;
+  padding-bottom: $custom-select-padding-y-sm;
+  padding-left: $custom-select-padding-x-sm;
+  @include font-size($custom-select-font-size-sm);
+}
+
+.custom-select-lg {
+  height: $custom-select-height-lg;
+  padding-top: $custom-select-padding-y-lg;
+  padding-bottom: $custom-select-padding-y-lg;
+  padding-left: $custom-select-padding-x-lg;
+  @include font-size($custom-select-font-size-lg);
+}
+
+
+// File
+//
+// Custom file input.
+
+.custom-file {
+  position: relative;
+  display: inline-block;
+  width: 100%;
+  height: $custom-file-height;
+  margin-bottom: 0;
+}
+
+.custom-file-input {
+  position: relative;
+  z-index: 2;
+  width: 100%;
+  height: $custom-file-height;
+  margin: 0;
+  opacity: 0;
+
+  &:focus ~ .custom-file-label {
+    border-color: $custom-file-focus-border-color;
+    box-shadow: $custom-file-focus-box-shadow;
+  }
+
+  &:disabled ~ .custom-file-label {
+    background-color: $custom-file-disabled-bg;
+  }
+
+  @each $lang, $value in $custom-file-text {
+    &:lang(#{$lang}) ~ .custom-file-label::after {
+      content: $value;
+    }
+  }
+
+  ~ .custom-file-label[data-browse]::after {
+    content: attr(data-browse);
+  }
+}
+
+.custom-file-label {
+  position: absolute;
+  top: 0;
+  right: 0;
+  left: 0;
+  z-index: 1;
+  height: $custom-file-height;
+  padding: $custom-file-padding-y $custom-file-padding-x;
+  font-family: $custom-file-font-family;
+  font-weight: $custom-file-font-weight;
+  line-height: $custom-file-line-height;
+  color: $custom-file-color;
+  background-color: $custom-file-bg;
+  border: $custom-file-border-width solid $custom-file-border-color;
+  @include border-radius($custom-file-border-radius);
+  @include box-shadow($custom-file-box-shadow);
+
+  &::after {
+    position: absolute;
+    top: 0;
+    right: 0;
+    bottom: 0;
+    z-index: 3;
+    display: block;
+    height: $custom-file-height-inner;
+    padding: $custom-file-padding-y $custom-file-padding-x;
+    line-height: $custom-file-line-height;
+    color: $custom-file-button-color;
+    content: "Browse";
+    @include gradient-bg($custom-file-button-bg);
+    border-left: inherit;
+    @include border-radius(0 $custom-file-border-radius $custom-file-border-radius 0);
+  }
+}
+
+// Range
+//
+// Style range inputs the same across browsers. Vendor-specific rules for pseudo
+// elements cannot be mixed. As such, there are no shared styles for focus or
+// active states on prefixed selectors.
+
+.custom-range {
+  width: 100%;
+  height: calc(#{$custom-range-thumb-height} + #{$custom-range-thumb-focus-box-shadow-width * 2});
+  padding: 0; // Need to reset padding
+  background-color: transparent;
+  appearance: none;
+
+  &:focus {
+    outline: none;
+
+    // Pseudo-elements must be split across multiple rulesets to have an effect.
+    // No box-shadow() mixin for focus accessibility.
+    &::-webkit-slider-thumb { box-shadow: $custom-range-thumb-focus-box-shadow; }
+    &::-moz-range-thumb     { box-shadow: $custom-range-thumb-focus-box-shadow; }
+    &::-ms-thumb            { box-shadow: $custom-range-thumb-focus-box-shadow; }
+  }
+
+  &::-moz-focus-outer {
+    border: 0;
+  }
+
+  &::-webkit-slider-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    margin-top: ($custom-range-track-height - $custom-range-thumb-height) / 2; // Webkit specific
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    @include transition($custom-forms-transition);
+    appearance: none;
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-webkit-slider-runnable-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent; // Why?
+    cursor: $custom-range-track-cursor;
+    background-color: $custom-range-track-bg;
+    border-color: transparent;
+    @include border-radius($custom-range-track-border-radius);
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-moz-range-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    @include transition($custom-forms-transition);
+    appearance: none;
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-moz-range-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent;
+    cursor: $custom-range-track-cursor;
+    background-color: $custom-range-track-bg;
+    border-color: transparent; // Firefox specific?
+    @include border-radius($custom-range-track-border-radius);
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-ms-thumb {
+    width: $custom-range-thumb-width;
+    height: $custom-range-thumb-height;
+    margin-top: 0; // Edge specific
+    margin-right: $custom-range-thumb-focus-box-shadow-width; // Workaround that overflowed box-shadow is hidden.
+    margin-left: $custom-range-thumb-focus-box-shadow-width;  // Workaround that overflowed box-shadow is hidden.
+    @include gradient-bg($custom-range-thumb-bg);
+    border: $custom-range-thumb-border;
+    @include border-radius($custom-range-thumb-border-radius);
+    @include box-shadow($custom-range-thumb-box-shadow);
+    @include transition($custom-forms-transition);
+    appearance: none;
+
+    &:active {
+      @include gradient-bg($custom-range-thumb-active-bg);
+    }
+  }
+
+  &::-ms-track {
+    width: $custom-range-track-width;
+    height: $custom-range-track-height;
+    color: transparent;
+    cursor: $custom-range-track-cursor;
+    background-color: transparent;
+    border-color: transparent;
+    border-width: $custom-range-thumb-height / 2;
+    @include box-shadow($custom-range-track-box-shadow);
+  }
+
+  &::-ms-fill-lower {
+    background-color: $custom-range-track-bg;
+    @include border-radius($custom-range-track-border-radius);
+  }
+
+  &::-ms-fill-upper {
+    margin-right: 15px; // arbitrary?
+    background-color: $custom-range-track-bg;
+    @include border-radius($custom-range-track-border-radius);
+  }
+
+  &:disabled {
+    &::-webkit-slider-thumb {
+      background-color: $custom-range-thumb-disabled-bg;
+    }
+
+    &::-webkit-slider-runnable-track {
+      cursor: default;
+    }
+
+    &::-moz-range-thumb {
+      background-color: $custom-range-thumb-disabled-bg;
+    }
+
+    &::-moz-range-track {
+      cursor: default;
+    }
+
+    &::-ms-thumb {
+      background-color: $custom-range-thumb-disabled-bg;
+    }
+  }
+}
+
+.custom-control-label::before,
+.custom-file-label,
+.custom-select {
+  @include transition($custom-forms-transition);
+}

example/static/vendor/bootstrap/scss/_dropdown.scss

@@ -0,0 +1,191 @@
+// The dropdown wrapper (`<div>`)
+.dropup,
+.dropright,
+.dropdown,
+.dropleft {
+  position: relative;
+}
+
+.dropdown-toggle {
+  white-space: nowrap;
+
+  // Generate the caret automatically
+  @include caret;
+}
+
+// The dropdown menu
+.dropdown-menu {
+  position: absolute;
+  top: 100%;
+  left: 0;
+  z-index: $zindex-dropdown;
+  display: none; // none by default, but block on "open" of the menu
+  float: left;
+  min-width: $dropdown-min-width;
+  padding: $dropdown-padding-y 0;
+  margin: $dropdown-spacer 0 0; // override default ul
+  @include font-size($dropdown-font-size);
+  color: $dropdown-color;
+  text-align: left; // Ensures proper alignment if parent has it changed (e.g., modal footer)
+  list-style: none;
+  background-color: $dropdown-bg;
+  background-clip: padding-box;
+  border: $dropdown-border-width solid $dropdown-border-color;
+  @include border-radius($dropdown-border-radius);
+  @include box-shadow($dropdown-box-shadow);
+}
+
+@each $breakpoint in map-keys($grid-breakpoints) {
+  @include media-breakpoint-up($breakpoint) {
+    $infix: breakpoint-infix($breakpoint, $grid-breakpoints);
+
+    .dropdown-menu#{$infix}-left {
+      right: auto;
+      left: 0;
+    }
+
+    .dropdown-menu#{$infix}-right {
+      right: 0;
+      left: auto;
+    }
+  }
+}
+
+// Allow for dropdowns to go bottom up (aka, dropup-menu)
+// Just add .dropup after the standard .dropdown class and you're set.
+.dropup {
+  .dropdown-menu {
+    top: auto;
+    bottom: 100%;
+    margin-top: 0;
+    margin-bottom: $dropdown-spacer;
+  }
+
+  .dropdown-toggle {
+    @include caret(up);
+  }
+}
+
+.dropright {
+  .dropdown-menu {
+    top: 0;
+    right: auto;
+    left: 100%;
+    margin-top: 0;
+    margin-left: $dropdown-spacer;
+  }
+
+  .dropdown-toggle {
+    @include caret(right);
+    &::after {
+      vertical-align: 0;
+    }
+  }
+}
+
+.dropleft {
+  .dropdown-menu {
+    top: 0;
+    right: 100%;
+    left: auto;
+    margin-top: 0;
+    margin-right: $dropdown-spacer;
+  }
+
+  .dropdown-toggle {
+    @include caret(left);
+    &::before {
+      vertical-align: 0;
+    }
+  }
+}
+
+// When enabled Popper.js, reset basic dropdown position
+// stylelint-disable-next-line no-duplicate-selectors
+.dropdown-menu {
+  &[x-placement^="top"],
+  &[x-placement^="right"],
+  &[x-placement^="bottom"],
+  &[x-placement^="left"] {
+    right: auto;
+    bottom: auto;
+  }
+}
+
+// Dividers (basically an `<hr>`) within the dropdown
+.dropdown-divider {
+  @include nav-divider($dropdown-divider-bg, $dropdown-divider-margin-y);
+}
+
+// Links, buttons, and more within the dropdown menu
+//
+// `<button>`-specific styles are denoted with `// For <button>s`
+.dropdown-item {
+  display: block;
+  width: 100%; // For `<button>`s
+  padding: $dropdown-item-padding-y $dropdown-item-padding-x;
+  clear: both;
+  font-weight: $font-weight-normal;
+  color: $dropdown-link-color;
+  text-align: inherit; // For `<button>`s
+  white-space: nowrap; // prevent links from randomly breaking onto new lines
+  background-color: transparent; // For `<button>`s
+  border: 0; // For `<button>`s
+
+  // Prevent dropdown overflow if there's no padding
+  // See https://github.com/twbs/bootstrap/pull/27703
+  @if $dropdown-padding-y == 0 {
+    &:first-child {
+      @include border-top-radius($dropdown-inner-border-radius);
+    }
+
+    &:last-child {
+      @include border-bottom-radius($dropdown-inner-border-radius);
+    }
+  }
+
+  @include hover-focus {
+    color: $dropdown-link-hover-color;
+    text-decoration: none;
+    @include gradient-bg($dropdown-link-hover-bg);
+  }
+
+  &.active,
+  &:active {
+    color: $dropdown-link-active-color;
+    text-decoration: none;
+    @include gradient-bg($dropdown-link-active-bg);
+  }
+
+  &.disabled,
+  &:disabled {
+    color: $dropdown-link-disabled-color;
+    pointer-events: none;
+    background-color: transparent;
+    // Remove CSS gradients if they're enabled
+    @if $enable-gradients {
+      background-image: none;
+    }
+  }
+}
+
+.dropdown-menu.show {
+  display: block;
+}
+
+// Dropdown section headers
+.dropdown-header {
+  display: block;
+  padding: $dropdown-padding-y $dropdown-item-padding-x;
+  margin-bottom: 0; // for use with heading elements
+  @include font-size($font-size-sm);
+  color: $dropdown-header-color;
+  white-space: nowrap; // as with > li > a
+}
+
+// Dropdown text
+.dropdown-item-text {
+  display: block;
+  padding: $dropdown-item-padding-y $dropdown-item-padding-x;
+  color: $dropdown-link-color;
+}

example/static/vendor/bootstrap/scss/_forms.scss

@@ -0,0 +1,330 @@
+// stylelint-disable selector-no-qualifying-type
+
+//
+// Textual form controls
+//
+
+.form-control {
+  display: block;
+  width: 100%;
+  height: $input-height;
+  padding: $input-padding-y $input-padding-x;
+  font-family: $input-font-family;
+  @include font-size($input-font-size);
+  font-weight: $input-font-weight;
+  line-height: $input-line-height;
+  color: $input-color;
+  background-color: $input-bg;
+  background-clip: padding-box;
+  border: $input-border-width solid $input-border-color;
+
+  // Note: This has no effect on <select>s in some browsers, due to the limited stylability of `<select>`s in CSS.
+  @include border-radius($input-border-radius, 0);
+
+  @include box-shadow($input-box-shadow);
+  @include transition($input-transition);
+
+  // Unstyle the caret on `<select>`s in IE10+.
+  &::-ms-expand {
+    background-color: transparent;
+    border: 0;
+  }
+
+  // Customize the `:focus` state to imitate native WebKit styles.
+  @include form-control-focus();
+
+  // Placeholder
+  &::placeholder {
+    color: $input-placeholder-color;
+    // Override Firefox's unusual default opacity; see https://github.com/twbs/bootstrap/pull/11526.
+    opacity: 1;
+  }
+
+  // Disabled and read-only inputs
+  //
+  // HTML5 says that controls under a fieldset > legend:first-child won't be
+  // disabled if the fieldset is disabled. Due to implementation difficulty, we
+  // don't honor that edge case; we style them as disabled anyway.
+  &:disabled,
+  &[readonly] {
+    background-color: $input-disabled-bg;
+    // iOS fix for unreadable disabled content; see https://github.com/twbs/bootstrap/issues/11655.
+    opacity: 1;
+  }
+}
+
+select.form-control {
+  &:focus::-ms-value {
+    // Suppress the nested default white text on blue background highlight given to
+    // the selected option text when the (still closed) <select> receives focus
+    // in IE and (under certain conditions) Edge, as it looks bad and cannot be made to
+    // match the appearance of the native widget.
+    // See https://github.com/twbs/bootstrap/issues/19398.
+    color: $input-color;
+    background-color: $input-bg;
+  }
+}
+
+// Make file inputs better match text inputs by forcing them to new lines.
+.form-control-file,
+.form-control-range {
+  display: block;
+  width: 100%;
+}
+
+
+//
+// Labels
+//
+
+// For use with horizontal and inline forms, when you need the label (or legend)
+// text to align with the form controls.
+.col-form-label {
+  padding-top: calc(#{$input-padding-y} + #{$input-border-width});
+  padding-bottom: calc(#{$input-padding-y} + #{$input-border-width});
+  margin-bottom: 0; // Override the `<label>/<legend>` default
+  @include font-size(inherit); // Override the `<legend>` default
+  line-height: $input-line-height;
+}
+
+.col-form-label-lg {
+  padding-top: calc(#{$input-padding-y-lg} + #{$input-border-width});
+  padding-bottom: calc(#{$input-padding-y-lg} + #{$input-border-width});
+  @include font-size($input-font-size-lg);
+  line-height: $input-line-height-lg;
+}
+
+.col-form-label-sm {
+  padding-top: calc(#{$input-padding-y-sm} + #{$input-border-width});
+  padding-bottom: calc(#{$input-padding-y-sm} + #{$input-border-width});
+  @include font-size($input-font-size-sm);
+  line-height: $input-line-height-sm;
+}
+
+
+// Readonly controls as plain text
+//
+// Apply class to a readonly input to make it appear like regular plain
+// text (without any border, background color, focus indicator)
+
+.form-control-plaintext {
+  display: block;
+  width: 100%;
+  padding-top: $input-padding-y;
+  padding-bottom: $input-padding-y;
+  margin-bottom: 0; // match inputs if this class comes on inputs with default margins
+  line-height: $input-line-height;
+  color: $input-plaintext-color;
+  background-color: transparent;
+  border: solid transparent;
+  border-width: $input-border-width 0;
+
+  &.form-control-sm,
+  &.form-control-lg {
+    padding-right: 0;
+    padding-left: 0;
+  }
+}
+
+
+// Form control sizing
+//
+// Build on `.form-control` with modifier classes to decrease or increase the
+// height and font-size of form controls.
+//
+// Repeated in `_input_group.scss` to avoid Sass extend issues.
+
+.form-control-sm {
+  height: $input-height-sm;
+  padding: $input-padding-y-sm $input-padding-x-sm;
+  @include font-size($input-font-size-sm);
+  line-height: $input-line-height-sm;
+  @include border-radius($input-border-radius-sm);
+}
+
+.form-control-lg {
+  height: $input-height-lg;
+  padding: $input-padding-y-lg $input-padding-x-lg;
+  @include font-size($input-font-size-lg);
+  line-height: $input-line-height-lg;
+  @include border-radius($input-border-radius-lg);
+}
+
+// stylelint-disable-next-line no-duplicate-selectors
+select.form-control {
+  &[size],
+  &[multiple] {
+    height: auto;
+  }
+}
+
+textarea.form-control {
+  height: auto;
+}
+
+// Form groups
+//
+// Designed to help with the organization and spacing of vertical forms. For
+// horizontal forms, use the predefined grid classes.
+
+.form-group {
+  margin-bottom: $form-group-margin-bottom;
+}
+
+.form-text {
+  display: block;
+  margin-top: $form-text-margin-top;
+}
+
+
+// Form grid
+//
+// Special replacement for our grid system's `.row` for tighter form layouts.
+
+.form-row {
+  display: flex;
+  flex-wrap: wrap;
+  margin-right: -$form-grid-gutter-width / 2;
+  margin-left: -$form-grid-gutter-width / 2;
+
+  > .col,
+  > [class*="col-"] {
+    padding-right: $form-grid-gutter-width / 2;
+    padding-left: $form-grid-gutter-width / 2;
+  }
+}
+
+
+// Checkboxes and radios
+//
+// Indent the labels to position radios/checkboxes as hanging controls.
+
+.form-check {
+  position: relative;
+  display: block;
+  padding-left: $form-check-input-gutter;
+}
+
+.form-check-input {
+  position: absolute;
+  margin-top: $form-check-input-margin-y;
+  margin-left: -$form-check-input-gutter;
+
+  &:disabled ~ .form-check-label {
+    color: $text-muted;
+  }
+}
+
+.form-check-label {
+  margin-bottom: 0; // Override default `<label>` bottom margin
+}
+
+.form-check-inline {
+  display: inline-flex;
+  align-items: center;
+  padding-left: 0; // Override base .form-check
+  margin-right: $form-check-inline-margin-x;
+
+  // Undo .form-check-input defaults and add some `margin-right`.
+  .form-check-input {
+    position: static;
+    margin-top: 0;
+    margin-right: $form-check-inline-input-margin-x;
+    margin-left: 0;
+  }
+}
+
+
+// Form validation
+//
+// Provide feedback to users when form field values are valid or invalid. Works
+// primarily for client-side validation via scoped `:invalid` and `:valid`
+// pseudo-classes but also includes `.is-invalid` and `.is-valid` classes for
+// server side validation.
+
+@each $state, $data in $form-validation-states {
+  @include form-validation-state($state, map-get($data, color), map-get($data, icon));
+}
+
+// Inline forms
+//
+// Make forms appear inline(-block) by adding the `.form-inline` class. Inline
+// forms begin stacked on extra small (mobile) devices and then go inline when
+// viewports reach <768px.
+//
+// Requires wrapping inputs and labels with `.form-group` for proper display of
+// default HTML form controls and our custom form controls (e.g., input groups).
+
+.form-inline {
+  display: flex;
+  flex-flow: row wrap;
+  align-items: center; // Prevent shorter elements from growing to same height as others (e.g., small buttons growing to normal sized button height)
+
+  // Because we use flex, the initial sizing of checkboxes is collapsed and
+  // doesn't occupy the full-width (which is what we want for xs grid tier),
+  // so we force that here.
+  .form-check {
+    width: 100%;
+  }
+
+  // Kick in the inline
+  @include media-breakpoint-up(sm) {
+    label {
+      display: flex;
+      align-items: center;
+      justify-content: center;
+      margin-bottom: 0;
+    }
+
+    // Inline-block all the things for "inline"
+    .form-group {
+      display: flex;
+      flex: 0 0 auto;
+      flex-flow: row wrap;
+      align-items: center;
+      margin-bottom: 0;
+    }
+
+    // Allow folks to *not* use `.form-group`
+    .form-control {
+      display: inline-block;
+      width: auto; // Prevent labels from stacking above inputs in `.form-group`
+      vertical-align: middle;
+    }
+
+    // Make static controls behave like regular ones
+    .form-control-plaintext {
+      display: inline-block;
+    }
+
+    .input-group,
+    .custom-select {
+      width: auto;
+    }
+
+    // Remove default margin on radios/checkboxes that were used for stacking, and
+    // then undo the floating of radios and checkboxes to match.
+    .form-check {
+      display: flex;
+      align-items: center;
+      justify-content: center;
+      width: auto;
+      padding-left: 0;
+    }
+    .form-check-input {
+      position: relative;
+      flex-shrink: 0;
+      margin-top: 0;
+      margin-right: $form-check-input-margin-x;
+      margin-left: 0;
+    }
+
+    .custom-control {
+      align-items: center;
+      justify-content: center;
+    }
+    .custom-control-label {
+      margin-bottom: 0;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_functions.scss

@@ -0,0 +1,86 @@
+// Bootstrap functions
+//
+// Utility mixins and functions for evaluating source code across our variables, maps, and mixins.
+
+// Ascending
+// Used to evaluate Sass maps like our grid breakpoints.
+@mixin _assert-ascending($map, $map-name) {
+  $prev-key: null;
+  $prev-num: null;
+  @each $key, $num in $map {
+    @if $prev-num == null or unit($num) == "%" {
+      // Do nothing
+    } @else if not comparable($prev-num, $num) {
+      @warn "Potentially invalid value for #{$map-name}: This map must be in ascending order, but key '#{$key}' has value #{$num} whose unit makes it incomparable to #{$prev-num}, the value of the previous key '#{$prev-key}' !";
+    } @else if $prev-num >= $num {
+      @warn "Invalid value for #{$map-name}: This map must be in ascending order, but key '#{$key}' has value #{$num} which isn't greater than #{$prev-num}, the value of the previous key '#{$prev-key}' !";
+    }
+    $prev-key: $key;
+    $prev-num: $num;
+  }
+}
+
+// Starts at zero
+// Used to ensure the min-width of the lowest breakpoint starts at 0.
+@mixin _assert-starts-at-zero($map, $map-name: "$grid-breakpoints") {
+  $values: map-values($map);
+  $first-value: nth($values, 1);
+  @if $first-value != 0 {
+    @warn "First breakpoint in #{$map-name} must start at 0, but starts at #{$first-value}.";
+  }
+}
+
+// Replace `$search` with `$replace` in `$string`
+// Used on our SVG icon backgrounds for custom forms.
+//
+// @author Hugo Giraudel
+// @param {String} $string - Initial string
+// @param {String} $search - Substring to replace
+// @param {String} $replace ('') - New value
+// @return {String} - Updated string
+@function str-replace($string, $search, $replace: "") {
+  $index: str-index($string, $search);
+
+  @if $index {
+    @return str-slice($string, 1, $index - 1) + $replace + str-replace(str-slice($string, $index + str-length($search)), $search, $replace);
+  }
+
+  @return $string;
+}
+
+// Color contrast
+@function color-yiq($color, $dark: $yiq-text-dark, $light: $yiq-text-light) {
+  $r: red($color);
+  $g: green($color);
+  $b: blue($color);
+
+  $yiq: (($r * 299) + ($g * 587) + ($b * 114)) / 1000;
+
+  @if ($yiq >= $yiq-contrasted-threshold) {
+    @return $dark;
+  } @else {
+    @return $light;
+  }
+}
+
+// Retrieve color Sass maps
+@function color($key: "blue") {
+  @return map-get($colors, $key);
+}
+
+@function theme-color($key: "primary") {
+  @return map-get($theme-colors, $key);
+}
+
+@function gray($key: "100") {
+  @return map-get($grays, $key);
+}
+
+// Request a theme color level
+@function theme-color-level($color-name: "primary", $level: 0) {
+  $color: theme-color($color-name);
+  $color-base: if($level > 0, $black, $white);
+  $level: abs($level);
+
+  @return mix($color-base, $color, $level * $theme-color-interval);
+}

example/static/vendor/bootstrap/scss/_grid.scss

@@ -0,0 +1,52 @@
+// Container widths
+//
+// Set the container width, and override it for fixed navbars in media queries.
+
+@if $enable-grid-classes {
+  .container {
+    @include make-container();
+    @include make-container-max-widths();
+  }
+}
+
+// Fluid container
+//
+// Utilizes the mixin meant for fixed width containers, but with 100% width for
+// fluid, full width layouts.
+
+@if $enable-grid-classes {
+  .container-fluid {
+    @include make-container();
+  }
+}
+
+// Row
+//
+// Rows contain and clear the floats of your columns.
+
+@if $enable-grid-classes {
+  .row {
+    @include make-row();
+  }
+
+  // Remove the negative margin from default .row, then the horizontal padding
+  // from all immediate children columns (to prevent runaway style inheritance).
+  .no-gutters {
+    margin-right: 0;
+    margin-left: 0;
+
+    > .col,
+    > [class*="col-"] {
+      padding-right: 0;
+      padding-left: 0;
+    }
+  }
+}
+
+// Columns
+//
+// Common styles for small and large grid columns
+
+@if $enable-grid-classes {
+  @include make-grid-columns();
+}

example/static/vendor/bootstrap/scss/_images.scss

@@ -0,0 +1,42 @@
+// Responsive images (ensure images don't scale beyond their parents)
+//
+// This is purposefully opt-in via an explicit class rather than being the default for all `<img>`s.
+// We previously tried the "images are responsive by default" approach in Bootstrap v2,
+// and abandoned it in Bootstrap v3 because it breaks lots of third-party widgets (including Google Maps)
+// which weren't expecting the images within themselves to be involuntarily resized.
+// See also https://github.com/twbs/bootstrap/issues/18178
+.img-fluid {
+  @include img-fluid;
+}
+
+
+// Image thumbnails
+.img-thumbnail {
+  padding: $thumbnail-padding;
+  background-color: $thumbnail-bg;
+  border: $thumbnail-border-width solid $thumbnail-border-color;
+  @include border-radius($thumbnail-border-radius);
+  @include box-shadow($thumbnail-box-shadow);
+
+  // Keep them at most 100% wide
+  @include img-fluid;
+}
+
+//
+// Figures
+//
+
+.figure {
+  // Ensures the caption's text aligns with the image.
+  display: inline-block;
+}
+
+.figure-img {
+  margin-bottom: $spacer / 2;
+  line-height: 1;
+}
+
+.figure-caption {
+  @include font-size($figure-caption-font-size);
+  color: $figure-caption-color;
+}

example/static/vendor/bootstrap/scss/_input-group.scss

@@ -0,0 +1,193 @@
+// stylelint-disable selector-no-qualifying-type
+
+//
+// Base styles
+//
+
+.input-group {
+  position: relative;
+  display: flex;
+  flex-wrap: wrap; // For form validation feedback
+  align-items: stretch;
+  width: 100%;
+
+  > .form-control,
+  > .form-control-plaintext,
+  > .custom-select,
+  > .custom-file {
+    position: relative; // For focus state's z-index
+    flex: 1 1 auto;
+    // Add width 1% and flex-basis auto to ensure that button will not wrap out
+    // the column. Applies to IE Edge+ and Firefox. Chrome does not require this.
+    width: 1%;
+    margin-bottom: 0;
+
+    + .form-control,
+    + .custom-select,
+    + .custom-file {
+      margin-left: -$input-border-width;
+    }
+  }
+
+  // Bring the "active" form control to the top of surrounding elements
+  > .form-control:focus,
+  > .custom-select:focus,
+  > .custom-file .custom-file-input:focus ~ .custom-file-label {
+    z-index: 3;
+  }
+
+  // Bring the custom file input above the label
+  > .custom-file .custom-file-input:focus {
+    z-index: 4;
+  }
+
+  > .form-control,
+  > .custom-select {
+    &:not(:last-child) { @include border-right-radius(0); }
+    &:not(:first-child) { @include border-left-radius(0); }
+  }
+
+  // Custom file inputs have more complex markup, thus requiring different
+  // border-radius overrides.
+  > .custom-file {
+    display: flex;
+    align-items: center;
+
+    &:not(:last-child) .custom-file-label,
+    &:not(:last-child) .custom-file-label::after { @include border-right-radius(0); }
+    &:not(:first-child) .custom-file-label { @include border-left-radius(0); }
+  }
+}
+
+
+// Prepend and append
+//
+// While it requires one extra layer of HTML for each, dedicated prepend and
+// append elements allow us to 1) be less clever, 2) simplify our selectors, and
+// 3) support HTML5 form validation.
+
+.input-group-prepend,
+.input-group-append {
+  display: flex;
+
+  // Ensure buttons are always above inputs for more visually pleasing borders.
+  // This isn't needed for `.input-group-text` since it shares the same border-color
+  // as our inputs.
+  .btn {
+    position: relative;
+    z-index: 2;
+
+    &:focus {
+      z-index: 3;
+    }
+  }
+
+  .btn + .btn,
+  .btn + .input-group-text,
+  .input-group-text + .input-group-text,
+  .input-group-text + .btn {
+    margin-left: -$input-border-width;
+  }
+}
+
+.input-group-prepend { margin-right: -$input-border-width; }
+.input-group-append { margin-left: -$input-border-width; }
+
+
+// Textual addons
+//
+// Serves as a catch-all element for any text or radio/checkbox input you wish
+// to prepend or append to an input.
+
+.input-group-text {
+  display: flex;
+  align-items: center;
+  padding: $input-padding-y $input-padding-x;
+  margin-bottom: 0; // Allow use of <label> elements by overriding our default margin-bottom
+  @include font-size($input-font-size); // Match inputs
+  font-weight: $font-weight-normal;
+  line-height: $input-line-height;
+  color: $input-group-addon-color;
+  text-align: center;
+  white-space: nowrap;
+  background-color: $input-group-addon-bg;
+  border: $input-border-width solid $input-group-addon-border-color;
+  @include border-radius($input-border-radius);
+
+  // Nuke default margins from checkboxes and radios to vertically center within.
+  input[type="radio"],
+  input[type="checkbox"] {
+    margin-top: 0;
+  }
+}
+
+
+// Sizing
+//
+// Remix the default form control sizing classes into new ones for easier
+// manipulation.
+
+.input-group-lg > .form-control:not(textarea),
+.input-group-lg > .custom-select {
+  height: $input-height-lg;
+}
+
+.input-group-lg > .form-control,
+.input-group-lg > .custom-select,
+.input-group-lg > .input-group-prepend > .input-group-text,
+.input-group-lg > .input-group-append > .input-group-text,
+.input-group-lg > .input-group-prepend > .btn,
+.input-group-lg > .input-group-append > .btn {
+  padding: $input-padding-y-lg $input-padding-x-lg;
+  @include font-size($input-font-size-lg);
+  line-height: $input-line-height-lg;
+  @include border-radius($input-border-radius-lg);
+}
+
+.input-group-sm > .form-control:not(textarea),
+.input-group-sm > .custom-select {
+  height: $input-height-sm;
+}
+
+.input-group-sm > .form-control,
+.input-group-sm > .custom-select,
+.input-group-sm > .input-group-prepend > .input-group-text,
+.input-group-sm > .input-group-append > .input-group-text,
+.input-group-sm > .input-group-prepend > .btn,
+.input-group-sm > .input-group-append > .btn {
+  padding: $input-padding-y-sm $input-padding-x-sm;
+  @include font-size($input-font-size-sm);
+  line-height: $input-line-height-sm;
+  @include border-radius($input-border-radius-sm);
+}
+
+.input-group-lg > .custom-select,
+.input-group-sm > .custom-select {
+  padding-right: $custom-select-padding-x + $custom-select-indicator-padding;
+}
+
+
+// Prepend and append rounded corners
+//
+// These rulesets must come after the sizing ones to properly override sm and lg
+// border-radius values when extending. They're more specific than we'd like
+// with the `.input-group >` part, but without it, we cannot override the sizing.
+
+
+.input-group > .input-group-prepend > .btn,
+.input-group > .input-group-prepend > .input-group-text,
+.input-group > .input-group-append:not(:last-child) > .btn,
+.input-group > .input-group-append:not(:last-child) > .input-group-text,
+.input-group > .input-group-append:last-child > .btn:not(:last-child):not(.dropdown-toggle),
+.input-group > .input-group-append:last-child > .input-group-text:not(:last-child) {
+  @include border-right-radius(0);
+}
+
+.input-group > .input-group-append > .btn,
+.input-group > .input-group-append > .input-group-text,
+.input-group > .input-group-prepend:not(:first-child) > .btn,
+.input-group > .input-group-prepend:not(:first-child) > .input-group-text,
+.input-group > .input-group-prepend:first-child > .btn:not(:first-child),
+.input-group > .input-group-prepend:first-child > .input-group-text:not(:first-child) {
+  @include border-left-radius(0);
+}

example/static/vendor/bootstrap/scss/_jumbotron.scss

@@ -0,0 +1,17 @@
+.jumbotron {
+  padding: $jumbotron-padding ($jumbotron-padding / 2);
+  margin-bottom: $jumbotron-padding;
+  color: $jumbotron-color;
+  background-color: $jumbotron-bg;
+  @include border-radius($border-radius-lg);
+
+  @include media-breakpoint-up(sm) {
+    padding: ($jumbotron-padding * 2) $jumbotron-padding;
+  }
+}
+
+.jumbotron-fluid {
+  padding-right: 0;
+  padding-left: 0;
+  @include border-radius(0);
+}

example/static/vendor/bootstrap/scss/_list-group.scss

@@ -0,0 +1,149 @@
+// Base class
+//
+// Easily usable on <ul>, <ol>, or <div>.
+
+.list-group {
+  display: flex;
+  flex-direction: column;
+
+  // No need to set list-style: none; since .list-group-item is block level
+  padding-left: 0; // reset padding because ul and ol
+  margin-bottom: 0;
+}
+
+
+// Interactive list items
+//
+// Use anchor or button elements instead of `li`s or `div`s to create interactive
+// list items. Includes an extra `.active` modifier class for selected items.
+
+.list-group-item-action {
+  width: 100%; // For `<button>`s (anchors become 100% by default though)
+  color: $list-group-action-color;
+  text-align: inherit; // For `<button>`s (anchors inherit)
+
+  // Hover state
+  @include hover-focus {
+    z-index: 1; // Place hover/focus items above their siblings for proper border styling
+    color: $list-group-action-hover-color;
+    text-decoration: none;
+    background-color: $list-group-hover-bg;
+  }
+
+  &:active {
+    color: $list-group-action-active-color;
+    background-color: $list-group-action-active-bg;
+  }
+}
+
+
+// Individual list items
+//
+// Use on `li`s or `div`s within the `.list-group` parent.
+
+.list-group-item {
+  position: relative;
+  display: block;
+  padding: $list-group-item-padding-y $list-group-item-padding-x;
+  // Place the border on the list items and negative margin up for better styling
+  margin-bottom: -$list-group-border-width;
+  color: $list-group-color;
+  background-color: $list-group-bg;
+  border: $list-group-border-width solid $list-group-border-color;
+
+  &:first-child {
+    @include border-top-radius($list-group-border-radius);
+  }
+
+  &:last-child {
+    margin-bottom: 0;
+    @include border-bottom-radius($list-group-border-radius);
+  }
+
+  &.disabled,
+  &:disabled {
+    color: $list-group-disabled-color;
+    pointer-events: none;
+    background-color: $list-group-disabled-bg;
+  }
+
+  // Include both here for `<a>`s and `<button>`s
+  &.active {
+    z-index: 2; // Place active items above their siblings for proper border styling
+    color: $list-group-active-color;
+    background-color: $list-group-active-bg;
+    border-color: $list-group-active-border-color;
+  }
+}
+
+
+// Horizontal
+//
+// Change the layout of list group items from vertical (default) to horizontal.
+
+@each $breakpoint in map-keys($grid-breakpoints) {
+  @include media-breakpoint-up($breakpoint) {
+    $infix: breakpoint-infix($breakpoint, $grid-breakpoints);
+
+    .list-group-horizontal#{$infix} {
+      flex-direction: row;
+
+      .list-group-item {
+        margin-right: -$list-group-border-width;
+        margin-bottom: 0;
+
+        &:first-child {
+          @include border-left-radius($list-group-border-radius);
+          @include border-top-right-radius(0);
+        }
+
+        &:last-child {
+          margin-right: 0;
+          @include border-right-radius($list-group-border-radius);
+          @include border-bottom-left-radius(0);
+        }
+      }
+    }
+  }
+}
+
+
+// Flush list items
+//
+// Remove borders and border-radius to keep list group items edge-to-edge. Most
+// useful within other components (e.g., cards).
+
+.list-group-flush {
+  .list-group-item {
+    border-right: 0;
+    border-left: 0;
+    @include border-radius(0);
+
+    &:last-child {
+      margin-bottom: -$list-group-border-width;
+    }
+  }
+
+  &:first-child {
+    .list-group-item:first-child {
+      border-top: 0;
+    }
+  }
+
+  &:last-child {
+    .list-group-item:last-child {
+      margin-bottom: 0;
+      border-bottom: 0;
+    }
+  }
+}
+
+
+// Contextual variants
+//
+// Add modifier classes to change text and background color on individual items.
+// Organizationally, this must come after the `:hover` states.
+
+@each $color, $value in $theme-colors {
+  @include list-group-item-variant($color, theme-color-level($color, -9), theme-color-level($color, 6));
+}

example/static/vendor/bootstrap/scss/_media.scss

@@ -0,0 +1,8 @@
+.media {
+  display: flex;
+  align-items: flex-start;
+}
+
+.media-body {
+  flex: 1;
+}

example/static/vendor/bootstrap/scss/_mixins.scss

@@ -0,0 +1,47 @@
+// Toggles
+//
+// Used in conjunction with global variables to enable certain theme features.
+
+// Vendor
+@import "vendor/rfs";
+
+// Deprecate
+@import "mixins/deprecate";
+
+// Utilities
+@import "mixins/breakpoints";
+@import "mixins/hover";
+@import "mixins/image";
+@import "mixins/badge";
+@import "mixins/resize";
+@import "mixins/screen-reader";
+@import "mixins/size";
+@import "mixins/reset-text";
+@import "mixins/text-emphasis";
+@import "mixins/text-hide";
+@import "mixins/text-truncate";
+@import "mixins/visibility";
+
+// // Components
+@import "mixins/alert";
+@import "mixins/buttons";
+@import "mixins/caret";
+@import "mixins/pagination";
+@import "mixins/lists";
+@import "mixins/list-group";
+@import "mixins/nav-divider";
+@import "mixins/forms";
+@import "mixins/table-row";
+
+// // Skins
+@import "mixins/background-variant";
+@import "mixins/border-radius";
+@import "mixins/box-shadow";
+@import "mixins/gradients";
+@import "mixins/transition";
+
+// // Layout
+@import "mixins/clearfix";
+@import "mixins/grid-framework";
+@import "mixins/grid";
+@import "mixins/float";

example/static/vendor/bootstrap/scss/_modal.scss

@@ -0,0 +1,229 @@
+// .modal-open      - body class for killing the scroll
+// .modal           - container to scroll within
+// .modal-dialog    - positioning shell for the actual modal
+// .modal-content   - actual modal w/ bg and corners and stuff
+
+
+.modal-open {
+  // Kill the scroll on the body
+  overflow: hidden;
+
+  .modal {
+    overflow-x: hidden;
+    overflow-y: auto;
+  }
+}
+
+// Container that the modal scrolls within
+.modal {
+  position: fixed;
+  top: 0;
+  left: 0;
+  z-index: $zindex-modal;
+  display: none;
+  width: 100%;
+  height: 100%;
+  overflow: hidden;
+  // Prevent Chrome on Windows from adding a focus outline. For details, see
+  // https://github.com/twbs/bootstrap/pull/10951.
+  outline: 0;
+  // We deliberately don't use `-webkit-overflow-scrolling: touch;` due to a
+  // gnarly iOS Safari bug: https://bugs.webkit.org/show_bug.cgi?id=158342
+  // See also https://github.com/twbs/bootstrap/issues/17695
+}
+
+// Shell div to position the modal with bottom padding
+.modal-dialog {
+  position: relative;
+  width: auto;
+  margin: $modal-dialog-margin;
+  // allow clicks to pass through for custom click handling to close modal
+  pointer-events: none;
+
+  // When fading in the modal, animate it to slide down
+  .modal.fade & {
+    @include transition($modal-transition);
+    transform: $modal-fade-transform;
+  }
+  .modal.show & {
+    transform: $modal-show-transform;
+  }
+}
+
+.modal-dialog-scrollable {
+  display: flex; // IE10/11
+  max-height: calc(100% - #{$modal-dialog-margin * 2});
+
+  .modal-content {
+    max-height: calc(100vh - #{$modal-dialog-margin * 2}); // IE10/11
+    overflow: hidden;
+  }
+
+  .modal-header,
+  .modal-footer {
+    flex-shrink: 0;
+  }
+
+  .modal-body {
+    overflow-y: auto;
+  }
+}
+
+.modal-dialog-centered {
+  display: flex;
+  align-items: center;
+  min-height: calc(100% - #{$modal-dialog-margin * 2});
+
+  // Ensure `modal-dialog-centered` extends the full height of the view (IE10/11)
+  &::before {
+    display: block; // IE10
+    height: calc(100vh - #{$modal-dialog-margin * 2});
+    content: "";
+  }
+
+  // Ensure `.modal-body` shows scrollbar (IE10/11)
+  &.modal-dialog-scrollable {
+    flex-direction: column;
+    justify-content: center;
+    height: 100%;
+
+    .modal-content {
+      max-height: none;
+    }
+
+    &::before {
+      content: none;
+    }
+  }
+}
+
+// Actual modal
+.modal-content {
+  position: relative;
+  display: flex;
+  flex-direction: column;
+  width: 100%; // Ensure `.modal-content` extends the full width of the parent `.modal-dialog`
+  // counteract the pointer-events: none; in the .modal-dialog
+  color: $modal-content-color;
+  pointer-events: auto;
+  background-color: $modal-content-bg;
+  background-clip: padding-box;
+  border: $modal-content-border-width solid $modal-content-border-color;
+  @include border-radius($modal-content-border-radius);
+  @include box-shadow($modal-content-box-shadow-xs);
+  // Remove focus outline from opened modal
+  outline: 0;
+}
+
+// Modal background
+.modal-backdrop {
+  position: fixed;
+  top: 0;
+  left: 0;
+  z-index: $zindex-modal-backdrop;
+  width: 100vw;
+  height: 100vh;
+  background-color: $modal-backdrop-bg;
+
+  // Fade for backdrop
+  &.fade { opacity: 0; }
+  &.show { opacity: $modal-backdrop-opacity; }
+}
+
+// Modal header
+// Top section of the modal w/ title and dismiss
+.modal-header {
+  display: flex;
+  align-items: flex-start; // so the close btn always stays on the upper right corner
+  justify-content: space-between; // Put modal header elements (title and dismiss) on opposite ends
+  padding: $modal-header-padding;
+  border-bottom: $modal-header-border-width solid $modal-header-border-color;
+  @include border-top-radius($modal-content-border-radius);
+
+  .close {
+    padding: $modal-header-padding;
+    // auto on the left force icon to the right even when there is no .modal-title
+    margin: (-$modal-header-padding-y) (-$modal-header-padding-x) (-$modal-header-padding-y) auto;
+  }
+}
+
+// Title text within header
+.modal-title {
+  margin-bottom: 0;
+  line-height: $modal-title-line-height;
+}
+
+// Modal body
+// Where all modal content resides (sibling of .modal-header and .modal-footer)
+.modal-body {
+  position: relative;
+  // Enable `flex-grow: 1` so that the body take up as much space as possible
+  // when should there be a fixed height on `.modal-dialog`.
+  flex: 1 1 auto;
+  padding: $modal-inner-padding;
+}
+
+// Footer (for actions)
+.modal-footer {
+  display: flex;
+  align-items: center; // vertically center
+  justify-content: flex-end; // Right align buttons with flex property because text-align doesn't work on flex items
+  padding: $modal-inner-padding;
+  border-top: $modal-footer-border-width solid $modal-footer-border-color;
+  @include border-bottom-radius($modal-content-border-radius);
+
+  // Easily place margin between footer elements
+  > :not(:first-child) { margin-left: .25rem; }
+  > :not(:last-child) { margin-right: .25rem; }
+}
+
+// Measure scrollbar width for padding body during modal show/hide
+.modal-scrollbar-measure {
+  position: absolute;
+  top: -9999px;
+  width: 50px;
+  height: 50px;
+  overflow: scroll;
+}
+
+// Scale up the modal
+@include media-breakpoint-up(sm) {
+  // Automatically set modal's width for larger viewports
+  .modal-dialog {
+    max-width: $modal-md;
+    margin: $modal-dialog-margin-y-sm-up auto;
+  }
+
+  .modal-dialog-scrollable {
+    max-height: calc(100% - #{$modal-dialog-margin-y-sm-up * 2});
+
+    .modal-content {
+      max-height: calc(100vh - #{$modal-dialog-margin-y-sm-up * 2});
+    }
+  }
+
+  .modal-dialog-centered {
+    min-height: calc(100% - #{$modal-dialog-margin-y-sm-up * 2});
+
+    &::before {
+      height: calc(100vh - #{$modal-dialog-margin-y-sm-up * 2});
+    }
+  }
+
+  .modal-content {
+    @include box-shadow($modal-content-box-shadow-sm-up);
+  }
+
+  .modal-sm { max-width: $modal-sm; }
+}
+
+@include media-breakpoint-up(lg) {
+  .modal-lg,
+  .modal-xl {
+    max-width: $modal-lg;
+  }
+}
+
+@include media-breakpoint-up(xl) {
+  .modal-xl { max-width: $modal-xl; }
+}

example/static/vendor/bootstrap/scss/_nav.scss

@@ -0,0 +1,120 @@
+// Base class
+//
+// Kickstart any navigation component with a set of style resets. Works with
+// `<nav>`s or `<ul>`s.
+
+.nav {
+  display: flex;
+  flex-wrap: wrap;
+  padding-left: 0;
+  margin-bottom: 0;
+  list-style: none;
+}
+
+.nav-link {
+  display: block;
+  padding: $nav-link-padding-y $nav-link-padding-x;
+
+  @include hover-focus {
+    text-decoration: none;
+  }
+
+  // Disabled state lightens text
+  &.disabled {
+    color: $nav-link-disabled-color;
+    pointer-events: none;
+    cursor: default;
+  }
+}
+
+//
+// Tabs
+//
+
+.nav-tabs {
+  border-bottom: $nav-tabs-border-width solid $nav-tabs-border-color;
+
+  .nav-item {
+    margin-bottom: -$nav-tabs-border-width;
+  }
+
+  .nav-link {
+    border: $nav-tabs-border-width solid transparent;
+    @include border-top-radius($nav-tabs-border-radius);
+
+    @include hover-focus {
+      border-color: $nav-tabs-link-hover-border-color;
+    }
+
+    &.disabled {
+      color: $nav-link-disabled-color;
+      background-color: transparent;
+      border-color: transparent;
+    }
+  }
+
+  .nav-link.active,
+  .nav-item.show .nav-link {
+    color: $nav-tabs-link-active-color;
+    background-color: $nav-tabs-link-active-bg;
+    border-color: $nav-tabs-link-active-border-color;
+  }
+
+  .dropdown-menu {
+    // Make dropdown border overlap tab border
+    margin-top: -$nav-tabs-border-width;
+    // Remove the top rounded corners here since there is a hard edge above the menu
+    @include border-top-radius(0);
+  }
+}
+
+
+//
+// Pills
+//
+
+.nav-pills {
+  .nav-link {
+    @include border-radius($nav-pills-border-radius);
+  }
+
+  .nav-link.active,
+  .show > .nav-link {
+    color: $nav-pills-link-active-color;
+    background-color: $nav-pills-link-active-bg;
+  }
+}
+
+
+//
+// Justified variants
+//
+
+.nav-fill {
+  .nav-item {
+    flex: 1 1 auto;
+    text-align: center;
+  }
+}
+
+.nav-justified {
+  .nav-item {
+    flex-basis: 0;
+    flex-grow: 1;
+    text-align: center;
+  }
+}
+
+
+// Tabbable tabs
+//
+// Hide tabbable panes to start, show them when `.active`
+
+.tab-content {
+  > .tab-pane {
+    display: none;
+  }
+  > .active {
+    display: block;
+  }
+}

example/static/vendor/bootstrap/scss/_navbar.scss

@@ -0,0 +1,294 @@
+// Contents
+//
+// Navbar
+// Navbar brand
+// Navbar nav
+// Navbar text
+// Navbar divider
+// Responsive navbar
+// Navbar position
+// Navbar themes
+
+
+// Navbar
+//
+// Provide a static navbar from which we expand to create full-width, fixed, and
+// other navbar variations.
+
+.navbar {
+  position: relative;
+  display: flex;
+  flex-wrap: wrap; // allow us to do the line break for collapsing content
+  align-items: center;
+  justify-content: space-between; // space out brand from logo
+  padding: $navbar-padding-y $navbar-padding-x;
+
+  // Because flex properties aren't inherited, we need to redeclare these first
+  // few properties so that content nested within behave properly.
+  > .container,
+  > .container-fluid {
+    display: flex;
+    flex-wrap: wrap;
+    align-items: center;
+    justify-content: space-between;
+  }
+}
+
+
+// Navbar brand
+//
+// Used for brand, project, or site names.
+
+.navbar-brand {
+  display: inline-block;
+  padding-top: $navbar-brand-padding-y;
+  padding-bottom: $navbar-brand-padding-y;
+  margin-right: $navbar-padding-x;
+  @include font-size($navbar-brand-font-size);
+  line-height: inherit;
+  white-space: nowrap;
+
+  @include hover-focus {
+    text-decoration: none;
+  }
+}
+
+
+// Navbar nav
+//
+// Custom navbar navigation (doesn't require `.nav`, but does make use of `.nav-link`).
+
+.navbar-nav {
+  display: flex;
+  flex-direction: column; // cannot use `inherit` to get the `.navbar`s value
+  padding-left: 0;
+  margin-bottom: 0;
+  list-style: none;
+
+  .nav-link {
+    padding-right: 0;
+    padding-left: 0;
+  }
+
+  .dropdown-menu {
+    position: static;
+    float: none;
+  }
+}
+
+
+// Navbar text
+//
+//
+
+.navbar-text {
+  display: inline-block;
+  padding-top: $nav-link-padding-y;
+  padding-bottom: $nav-link-padding-y;
+}
+
+
+// Responsive navbar
+//
+// Custom styles for responsive collapsing and toggling of navbar contents.
+// Powered by the collapse Bootstrap JavaScript plugin.
+
+// When collapsed, prevent the toggleable navbar contents from appearing in
+// the default flexbox row orientation. Requires the use of `flex-wrap: wrap`
+// on the `.navbar` parent.
+.navbar-collapse {
+  flex-basis: 100%;
+  flex-grow: 1;
+  // For always expanded or extra full navbars, ensure content aligns itself
+  // properly vertically. Can be easily overridden with flex utilities.
+  align-items: center;
+}
+
+// Button for toggling the navbar when in its collapsed state
+.navbar-toggler {
+  padding: $navbar-toggler-padding-y $navbar-toggler-padding-x;
+  @include font-size($navbar-toggler-font-size);
+  line-height: 1;
+  background-color: transparent; // remove default button style
+  border: $border-width solid transparent; // remove default button style
+  @include border-radius($navbar-toggler-border-radius);
+
+  @include hover-focus {
+    text-decoration: none;
+  }
+}
+
+// Keep as a separate element so folks can easily override it with another icon
+// or image file as needed.
+.navbar-toggler-icon {
+  display: inline-block;
+  width: 1.5em;
+  height: 1.5em;
+  vertical-align: middle;
+  content: "";
+  background: no-repeat center center;
+  background-size: 100% 100%;
+}
+
+// Generate series of `.navbar-expand-*` responsive classes for configuring
+// where your navbar collapses.
+.navbar-expand {
+  @each $breakpoint in map-keys($grid-breakpoints) {
+    $next: breakpoint-next($breakpoint, $grid-breakpoints);
+    $infix: breakpoint-infix($next, $grid-breakpoints);
+
+    &#{$infix} {
+      @include media-breakpoint-down($breakpoint) {
+        > .container,
+        > .container-fluid {
+          padding-right: 0;
+          padding-left: 0;
+        }
+      }
+
+      @include media-breakpoint-up($next) {
+        flex-flow: row nowrap;
+        justify-content: flex-start;
+
+        .navbar-nav {
+          flex-direction: row;
+
+          .dropdown-menu {
+            position: absolute;
+          }
+
+          .nav-link {
+            padding-right: $navbar-nav-link-padding-x;
+            padding-left: $navbar-nav-link-padding-x;
+          }
+        }
+
+        // For nesting containers, have to redeclare for alignment purposes
+        > .container,
+        > .container-fluid {
+          flex-wrap: nowrap;
+        }
+
+        .navbar-collapse {
+          display: flex !important; // stylelint-disable-line declaration-no-important
+
+          // Changes flex-bases to auto because of an IE10 bug
+          flex-basis: auto;
+        }
+
+        .navbar-toggler {
+          display: none;
+        }
+      }
+    }
+  }
+}
+
+
+// Navbar themes
+//
+// Styles for switching between navbars with light or dark background.
+
+// Dark links against a light background
+.navbar-light {
+  .navbar-brand {
+    color: $navbar-light-brand-color;
+
+    @include hover-focus {
+      color: $navbar-light-brand-hover-color;
+    }
+  }
+
+  .navbar-nav {
+    .nav-link {
+      color: $navbar-light-color;
+
+      @include hover-focus {
+        color: $navbar-light-hover-color;
+      }
+
+      &.disabled {
+        color: $navbar-light-disabled-color;
+      }
+    }
+
+    .show > .nav-link,
+    .active > .nav-link,
+    .nav-link.show,
+    .nav-link.active {
+      color: $navbar-light-active-color;
+    }
+  }
+
+  .navbar-toggler {
+    color: $navbar-light-color;
+    border-color: $navbar-light-toggler-border-color;
+  }
+
+  .navbar-toggler-icon {
+    background-image: $navbar-light-toggler-icon-bg;
+  }
+
+  .navbar-text {
+    color: $navbar-light-color;
+    a {
+      color: $navbar-light-active-color;
+
+      @include hover-focus {
+        color: $navbar-light-active-color;
+      }
+    }
+  }
+}
+
+// White links against a dark background
+.navbar-dark {
+  .navbar-brand {
+    color: $navbar-dark-brand-color;
+
+    @include hover-focus {
+      color: $navbar-dark-brand-hover-color;
+    }
+  }
+
+  .navbar-nav {
+    .nav-link {
+      color: $navbar-dark-color;
+
+      @include hover-focus {
+        color: $navbar-dark-hover-color;
+      }
+
+      &.disabled {
+        color: $navbar-dark-disabled-color;
+      }
+    }
+
+    .show > .nav-link,
+    .active > .nav-link,
+    .nav-link.show,
+    .nav-link.active {
+      color: $navbar-dark-active-color;
+    }
+  }
+
+  .navbar-toggler {
+    color: $navbar-dark-color;
+    border-color: $navbar-dark-toggler-border-color;
+  }
+
+  .navbar-toggler-icon {
+    background-image: $navbar-dark-toggler-icon-bg;
+  }
+
+  .navbar-text {
+    color: $navbar-dark-color;
+    a {
+      color: $navbar-dark-active-color;
+
+      @include hover-focus {
+        color: $navbar-dark-active-color;
+      }
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_pagination.scss

@@ -0,0 +1,73 @@
+.pagination {
+  display: flex;
+  @include list-unstyled();
+  @include border-radius();
+}
+
+.page-link {
+  position: relative;
+  display: block;
+  padding: $pagination-padding-y $pagination-padding-x;
+  margin-left: -$pagination-border-width;
+  line-height: $pagination-line-height;
+  color: $pagination-color;
+  background-color: $pagination-bg;
+  border: $pagination-border-width solid $pagination-border-color;
+
+  &:hover {
+    z-index: 2;
+    color: $pagination-hover-color;
+    text-decoration: none;
+    background-color: $pagination-hover-bg;
+    border-color: $pagination-hover-border-color;
+  }
+
+  &:focus {
+    z-index: 2;
+    outline: $pagination-focus-outline;
+    box-shadow: $pagination-focus-box-shadow;
+  }
+}
+
+.page-item {
+  &:first-child {
+    .page-link {
+      margin-left: 0;
+      @include border-left-radius($border-radius);
+    }
+  }
+  &:last-child {
+    .page-link {
+      @include border-right-radius($border-radius);
+    }
+  }
+
+  &.active .page-link {
+    z-index: 1;
+    color: $pagination-active-color;
+    background-color: $pagination-active-bg;
+    border-color: $pagination-active-border-color;
+  }
+
+  &.disabled .page-link {
+    color: $pagination-disabled-color;
+    pointer-events: none;
+    // Opinionated: remove the "hand" cursor set previously for .page-link
+    cursor: auto;
+    background-color: $pagination-disabled-bg;
+    border-color: $pagination-disabled-border-color;
+  }
+}
+
+
+//
+// Sizing
+//
+
+.pagination-lg {
+  @include pagination-size($pagination-padding-y-lg, $pagination-padding-x-lg, $font-size-lg, $line-height-lg, $border-radius-lg);
+}
+
+.pagination-sm {
+  @include pagination-size($pagination-padding-y-sm, $pagination-padding-x-sm, $font-size-sm, $line-height-sm, $border-radius-sm);
+}

example/static/vendor/bootstrap/scss/_popover.scss

@@ -0,0 +1,171 @@
+.popover {
+  position: absolute;
+  top: 0;
+  left: 0;
+  z-index: $zindex-popover;
+  display: block;
+  max-width: $popover-max-width;
+  // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
+  // So reset our font and text properties to avoid inheriting weird values.
+  @include reset-text();
+  @include font-size($popover-font-size);
+  // Allow breaking very long words so they don't overflow the popover's bounds
+  word-wrap: break-word;
+  background-color: $popover-bg;
+  background-clip: padding-box;
+  border: $popover-border-width solid $popover-border-color;
+  @include border-radius($popover-border-radius);
+  @include box-shadow($popover-box-shadow);
+
+  .arrow {
+    position: absolute;
+    display: block;
+    width: $popover-arrow-width;
+    height: $popover-arrow-height;
+    margin: 0 $border-radius-lg;
+
+    &::before,
+    &::after {
+      position: absolute;
+      display: block;
+      content: "";
+      border-color: transparent;
+      border-style: solid;
+    }
+  }
+}
+
+.bs-popover-top {
+  margin-bottom: $popover-arrow-height;
+
+  > .arrow {
+    bottom: calc((#{$popover-arrow-height} + #{$popover-border-width}) * -1);
+
+    &::before {
+      bottom: 0;
+      border-width: $popover-arrow-height ($popover-arrow-width / 2) 0;
+      border-top-color: $popover-arrow-outer-color;
+    }
+
+    &::after {
+      bottom: $popover-border-width;
+      border-width: $popover-arrow-height ($popover-arrow-width / 2) 0;
+      border-top-color: $popover-arrow-color;
+    }
+  }
+}
+
+.bs-popover-right {
+  margin-left: $popover-arrow-height;
+
+  > .arrow {
+    left: calc((#{$popover-arrow-height} + #{$popover-border-width}) * -1);
+    width: $popover-arrow-height;
+    height: $popover-arrow-width;
+    margin: $border-radius-lg 0; // make sure the arrow does not touch the popover's rounded corners
+
+    &::before {
+      left: 0;
+      border-width: ($popover-arrow-width / 2) $popover-arrow-height ($popover-arrow-width / 2) 0;
+      border-right-color: $popover-arrow-outer-color;
+    }
+
+    &::after {
+      left: $popover-border-width;
+      border-width: ($popover-arrow-width / 2) $popover-arrow-height ($popover-arrow-width / 2) 0;
+      border-right-color: $popover-arrow-color;
+    }
+  }
+}
+
+.bs-popover-bottom {
+  margin-top: $popover-arrow-height;
+
+  > .arrow {
+    top: calc((#{$popover-arrow-height} + #{$popover-border-width}) * -1);
+
+    &::before {
+      top: 0;
+      border-width: 0 ($popover-arrow-width / 2) $popover-arrow-height ($popover-arrow-width / 2);
+      border-bottom-color: $popover-arrow-outer-color;
+    }
+
+    &::after {
+      top: $popover-border-width;
+      border-width: 0 ($popover-arrow-width / 2) $popover-arrow-height ($popover-arrow-width / 2);
+      border-bottom-color: $popover-arrow-color;
+    }
+  }
+
+  // This will remove the popover-header's border just below the arrow
+  .popover-header::before {
+    position: absolute;
+    top: 0;
+    left: 50%;
+    display: block;
+    width: $popover-arrow-width;
+    margin-left: -$popover-arrow-width / 2;
+    content: "";
+    border-bottom: $popover-border-width solid $popover-header-bg;
+  }
+}
+
+.bs-popover-left {
+  margin-right: $popover-arrow-height;
+
+  > .arrow {
+    right: calc((#{$popover-arrow-height} + #{$popover-border-width}) * -1);
+    width: $popover-arrow-height;
+    height: $popover-arrow-width;
+    margin: $border-radius-lg 0; // make sure the arrow does not touch the popover's rounded corners
+
+    &::before {
+      right: 0;
+      border-width: ($popover-arrow-width / 2) 0 ($popover-arrow-width / 2) $popover-arrow-height;
+      border-left-color: $popover-arrow-outer-color;
+    }
+
+    &::after {
+      right: $popover-border-width;
+      border-width: ($popover-arrow-width / 2) 0 ($popover-arrow-width / 2) $popover-arrow-height;
+      border-left-color: $popover-arrow-color;
+    }
+  }
+}
+
+.bs-popover-auto {
+  &[x-placement^="top"] {
+    @extend .bs-popover-top;
+  }
+  &[x-placement^="right"] {
+    @extend .bs-popover-right;
+  }
+  &[x-placement^="bottom"] {
+    @extend .bs-popover-bottom;
+  }
+  &[x-placement^="left"] {
+    @extend .bs-popover-left;
+  }
+}
+
+
+// Offset the popover to account for the popover arrow
+.popover-header {
+  padding: $popover-header-padding-y $popover-header-padding-x;
+  margin-bottom: 0; // Reset the default from Reboot
+  @include font-size($font-size-base);
+  color: $popover-header-color;
+  background-color: $popover-header-bg;
+  border-bottom: $popover-border-width solid darken($popover-header-bg, 5%);
+  $offset-border-width: calc(#{$border-radius-lg} - #{$popover-border-width});
+  @include border-top-radius($offset-border-width);
+
+  &:empty {
+    display: none;
+  }
+}
+
+.popover-body {
+  padding: $popover-body-padding-y $popover-body-padding-x;
+  color: $popover-body-color;
+}

example/static/vendor/bootstrap/scss/_print.scss

@@ -0,0 +1,141 @@
+// stylelint-disable declaration-no-important, selector-no-qualifying-type
+
+// Source: https://github.com/h5bp/html5-boilerplate/blob/master/src/css/main.css
+
+// ==========================================================================
+// Print styles.
+// Inlined to avoid the additional HTTP request:
+// https://www.phpied.com/delay-loading-your-print-css/
+// ==========================================================================
+
+@if $enable-print-styles {
+  @media print {
+    *,
+    *::before,
+    *::after {
+      // Bootstrap specific; comment out `color` and `background`
+      //color: $black !important; // Black prints faster
+      text-shadow: none !important;
+      //background: transparent !important;
+      box-shadow: none !important;
+    }
+
+    a {
+      &:not(.btn) {
+        text-decoration: underline;
+      }
+    }
+
+    // Bootstrap specific; comment the following selector out
+    //a[href]::after {
+    //  content: " (" attr(href) ")";
+    //}
+
+    abbr[title]::after {
+      content: " (" attr(title) ")";
+    }
+
+    // Bootstrap specific; comment the following selector out
+    //
+    // Don't show links that are fragment identifiers,
+    // or use the `javascript:` pseudo protocol
+    //
+
+    //a[href^="#"]::after,
+    //a[href^="javascript:"]::after {
+    // content: "";
+    //}
+
+    pre {
+      white-space: pre-wrap !important;
+    }
+    pre,
+    blockquote {
+      border: $border-width solid $gray-500; // Bootstrap custom code; using `$border-width` instead of 1px
+      page-break-inside: avoid;
+    }
+
+    //
+    // Printing Tables:
+    // http://css-discuss.incutio.com/wiki/Printing_Tables
+    //
+
+    thead {
+      display: table-header-group;
+    }
+
+    tr,
+    img {
+      page-break-inside: avoid;
+    }
+
+    p,
+    h2,
+    h3 {
+      orphans: 3;
+      widows: 3;
+    }
+
+    h2,
+    h3 {
+      page-break-after: avoid;
+    }
+
+    // Bootstrap specific changes start
+
+    // Specify a size and min-width to make printing closer across browsers.
+    // We don't set margin here because it breaks `size` in Chrome. We also
+    // don't use `!important` on `size` as it breaks in Chrome.
+    @page {
+      size: $print-page-size;
+    }
+    body {
+      min-width: $print-body-min-width !important;
+    }
+    .container {
+      min-width: $print-body-min-width !important;
+    }
+
+    // Bootstrap components
+    .navbar {
+      display: none;
+    }
+    .badge {
+      border: $border-width solid $black;
+    }
+
+    .table {
+      border-collapse: collapse !important;
+
+      td,
+      th {
+        background-color: $white !important;
+      }
+    }
+
+    .table-bordered {
+      th,
+      td {
+        border: 1px solid $gray-300 !important;
+      }
+    }
+
+    .table-dark {
+      color: inherit;
+
+      th,
+      td,
+      thead th,
+      tbody + tbody {
+        border-color: $table-border-color;
+      }
+    }
+
+    .table .thead-dark th {
+      color: inherit;
+      border-color: $table-border-color;
+    }
+
+    // Bootstrap specific changes end
+  }
+}

example/static/vendor/bootstrap/scss/_progress.scss

@@ -0,0 +1,43 @@
+// Disable animation if transitions are disabled
+@if $enable-transitions {
+  @keyframes progress-bar-stripes {
+    from { background-position: $progress-height 0; }
+    to { background-position: 0 0; }
+  }
+}
+
+.progress {
+  display: flex;
+  height: $progress-height;
+  overflow: hidden; // force rounded corners by cropping it
+  @include font-size($progress-font-size);
+  background-color: $progress-bg;
+  @include border-radius($progress-border-radius);
+  @include box-shadow($progress-box-shadow);
+}
+
+.progress-bar {
+  display: flex;
+  flex-direction: column;
+  justify-content: center;
+  color: $progress-bar-color;
+  text-align: center;
+  white-space: nowrap;
+  background-color: $progress-bar-bg;
+  @include transition($progress-bar-transition);
+}
+
+.progress-bar-striped {
+  @include gradient-striped();
+  background-size: $progress-height $progress-height;
+}
+
+@if $enable-transitions {
+  .progress-bar-animated {
+    animation: progress-bar-stripes $progress-bar-animation-timing;
+
+    @media (prefers-reduced-motion: reduce) {
+      animation: none;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_reboot.scss

@@ -0,0 +1,483 @@
+// stylelint-disable at-rule-no-vendor-prefix, declaration-no-important, selector-no-qualifying-type, property-no-vendor-prefix
+
+// Reboot
+//
+// Normalization of HTML elements, manually forked from Normalize.css to remove
+// styles targeting irrelevant browsers while applying new styles.
+//
+// Normalize is licensed MIT. https://github.com/necolas/normalize.css
+
+
+// Document
+//
+// 1. Change from `box-sizing: content-box` so that `width` is not affected by `padding` or `border`.
+// 2. Change the default font family in all browsers.
+// 3. Correct the line height in all browsers.
+// 4. Prevent adjustments of font size after orientation changes in IE on Windows Phone and in iOS.
+// 5. Change the default tap highlight to be completely transparent in iOS.
+
+*,
+*::before,
+*::after {
+  box-sizing: border-box; // 1
+}
+
+html {
+  font-family: sans-serif; // 2
+  line-height: 1.15; // 3
+  -webkit-text-size-adjust: 100%; // 4
+  -webkit-tap-highlight-color: rgba($black, 0); // 5
+}
+
+// Shim for "new" HTML5 structural elements to display correctly (IE10, older browsers)
+// TODO: remove in v5
+// stylelint-disable-next-line selector-list-comma-newline-after
+article, aside, figcaption, figure, footer, header, hgroup, main, nav, section {
+  display: block;
+}
+
+// Body
+//
+// 1. Remove the margin in all browsers.
+// 2. As a best practice, apply a default `background-color`.
+// 3. Set an explicit initial text-align value so that we can later use
+//    the `inherit` value on things like `<th>` elements.
+
+body {
+  margin: 0; // 1
+  font-family: $font-family-base;
+  @include font-size($font-size-base);
+  font-weight: $font-weight-base;
+  line-height: $line-height-base;
+  color: $body-color;
+  text-align: left; // 3
+  background-color: $body-bg; // 2
+}
+
+// Suppress the focus outline on elements that cannot be accessed via keyboard.
+// This prevents an unwanted focus outline from appearing around elements that
+// might still respond to pointer events.
+//
+// Credit: https://github.com/suitcss/base
+[tabindex="-1"]:focus {
+  outline: 0 !important;
+}
+
+
+// Content grouping
+//
+// 1. Add the correct box sizing in Firefox.
+// 2. Show the overflow in Edge and IE.
+
+hr {
+  box-sizing: content-box; // 1
+  height: 0; // 1
+  overflow: visible; // 2
+}
+
+
+//
+// Typography
+//
+
+// Remove top margins from headings
+//
+// By default, `<h1>`-`<h6>` all receive top and bottom margins. We nuke the top
+// margin for easier control within type scales as it avoids margin collapsing.
+// stylelint-disable-next-line selector-list-comma-newline-after
+h1, h2, h3, h4, h5, h6 {
+  margin-top: 0;
+  margin-bottom: $headings-margin-bottom;
+}
+
+// Reset margins on paragraphs
+//
+// Similarly, the top margin on `<p>`s get reset. However, we also reset the
+// bottom margin to use `rem` units instead of `em`.
+p {
+  margin-top: 0;
+  margin-bottom: $paragraph-margin-bottom;
+}
+
+// Abbreviations
+//
+// 1. Duplicate behavior to the data-* attribute for our tooltip plugin
+// 2. Add the correct text decoration in Chrome, Edge, IE, Opera, and Safari.
+// 3. Add explicit cursor to indicate changed behavior.
+// 4. Remove the bottom border in Firefox 39-.
+// 5. Prevent the text-decoration to be skipped.
+
+abbr[title],
+abbr[data-original-title] { // 1
+  text-decoration: underline; // 2
+  text-decoration: underline dotted; // 2
+  cursor: help; // 3
+  border-bottom: 0; // 4
+  text-decoration-skip-ink: none; // 5
+}
+
+address {
+  margin-bottom: 1rem;
+  font-style: normal;
+  line-height: inherit;
+}
+
+ol,
+ul,
+dl {
+  margin-top: 0;
+  margin-bottom: 1rem;
+}
+
+ol ol,
+ul ul,
+ol ul,
+ul ol {
+  margin-bottom: 0;
+}
+
+dt {
+  font-weight: $dt-font-weight;
+}
+
+dd {
+  margin-bottom: .5rem;
+  margin-left: 0; // Undo browser default
+}
+
+blockquote {
+  margin: 0 0 1rem;
+}
+
+b,
+strong {
+  font-weight: $font-weight-bolder; // Add the correct font weight in Chrome, Edge, and Safari
+}
+
+small {
+  @include font-size(80%); // Add the correct font size in all browsers
+}
+
+//
+// Prevent `sub` and `sup` elements from affecting the line height in
+// all browsers.
+//
+
+sub,
+sup {
+  position: relative;
+  @include font-size(75%);
+  line-height: 0;
+  vertical-align: baseline;
+}
+
+sub { bottom: -.25em; }
+sup { top: -.5em; }
+
+
+//
+// Links
+//
+
+a {
+  color: $link-color;
+  text-decoration: $link-decoration;
+  background-color: transparent; // Remove the gray background on active links in IE 10.
+
+  @include hover {
+    color: $link-hover-color;
+    text-decoration: $link-hover-decoration;
+  }
+}
+
+// And undo these styles for placeholder links/named anchors (without href)
+// which have not been made explicitly keyboard-focusable (without tabindex).
+// It would be more straightforward to just use a[href] in previous block, but that
+// causes specificity issues in many other styles that are too complex to fix.
+// See https://github.com/twbs/bootstrap/issues/19402
+
+a:not([href]):not([tabindex]) {
+  color: inherit;
+  text-decoration: none;
+
+  @include hover-focus {
+    color: inherit;
+    text-decoration: none;
+  }
+
+  &:focus {
+    outline: 0;
+  }
+}
+
+
+//
+// Code
+//
+
+pre,
+code,
+kbd,
+samp {
+  font-family: $font-family-monospace;
+  @include font-size(1em); // Correct the odd `em` font sizing in all browsers.
+}
+
+pre {
+  // Remove browser default top margin
+  margin-top: 0;
+  // Reset browser default of `1em` to use `rem`s
+  margin-bottom: 1rem;
+  // Don't allow content to break outside
+  overflow: auto;
+}
+
+
+//
+// Figures
+//
+
+figure {
+  // Apply a consistent margin strategy (matches our type styles).
+  margin: 0 0 1rem;
+}
+
+
+//
+// Images and content
+//
+
+img {
+  vertical-align: middle;
+  border-style: none; // Remove the border on images inside links in IE 10-.
+}
+
+svg {
+  // Workaround for the SVG overflow bug in IE10/11 is still required.
+  // See https://github.com/twbs/bootstrap/issues/26878
+  overflow: hidden;
+  vertical-align: middle;
+}
+
+
+//
+// Tables
+//
+
+table {
+  border-collapse: collapse; // Prevent double borders
+}
+
+caption {
+  padding-top: $table-cell-padding;
+  padding-bottom: $table-cell-padding;
+  color: $table-caption-color;
+  text-align: left;
+  caption-side: bottom;
+}
+
+th {
+  // Matches default `<td>` alignment by inheriting from the `<body>`, or the
+  // closest parent with a set `text-align`.
+  text-align: inherit;
+}
+
+
+//
+// Forms
+//
+
+label {
+  // Allow labels to use `margin` for spacing.
+  display: inline-block;
+  margin-bottom: $label-margin-bottom;
+}
+
+// Remove the default `border-radius` that macOS Chrome adds.
+//
+// Details at https://github.com/twbs/bootstrap/issues/24093
+button {
+  // stylelint-disable-next-line property-blacklist
+  border-radius: 0;
+}
+
+// Work around a Firefox/IE bug where the transparent `button` background
+// results in a loss of the default `button` focus styles.
+//
+// Credit: https://github.com/suitcss/base/
+button:focus {
+  outline: 1px dotted;
+  outline: 5px auto -webkit-focus-ring-color;
+}
+
+input,
+button,
+select,
+optgroup,
+textarea {
+  margin: 0; // Remove the margin in Firefox and Safari
+  font-family: inherit;
+  @include font-size(inherit);
+  line-height: inherit;
+}
+
+button,
+input {
+  overflow: visible; // Show the overflow in Edge
+}
+
+button,
+select {
+  text-transform: none; // Remove the inheritance of text transform in Firefox
+}
+
+// Remove the inheritance of word-wrap in Safari.
+//
+// Details at https://github.com/twbs/bootstrap/issues/24990
+select {
+  word-wrap: normal;
+}
+
+
+// 1. Prevent a WebKit bug where (2) destroys native `audio` and `video`
+//    controls in Android 4.
+// 2. Correct the inability to style clickable types in iOS and Safari.
+button,
+[type="button"], // 1
+[type="reset"],
+[type="submit"] {
+  -webkit-appearance: button; // 2
+}
+
+// Opinionated: add "hand" cursor to non-disabled button elements.
+@if $enable-pointer-cursor-for-buttons {
+  button,
+  [type="button"],
+  [type="reset"],
+  [type="submit"] {
+    &:not(:disabled) {
+      cursor: pointer;
+    }
+  }
+}
+
+// Remove inner border and padding from Firefox, but don't restore the outline like Normalize.
+button::-moz-focus-inner,
+[type="button"]::-moz-focus-inner,
+[type="reset"]::-moz-focus-inner,
+[type="submit"]::-moz-focus-inner {
+  padding: 0;
+  border-style: none;
+}
+
+input[type="radio"],
+input[type="checkbox"] {
+  box-sizing: border-box; // 1. Add the correct box sizing in IE 10-
+  padding: 0; // 2. Remove the padding in IE 10-
+}
+
+
+input[type="date"],
+input[type="time"],
+input[type="datetime-local"],
+input[type="month"] {
+  // Remove the default appearance of temporal inputs to avoid a Mobile Safari
+  // bug where setting a custom line-height prevents text from being vertically
+  // centered within the input.
+  // See https://bugs.webkit.org/show_bug.cgi?id=139848
+  // and https://github.com/twbs/bootstrap/issues/11266
+  -webkit-appearance: listbox;
+}
+
+textarea {
+  overflow: auto; // Remove the default vertical scrollbar in IE.
+  // Textareas should really only resize vertically so they don't break their (horizontal) containers.
+  resize: vertical;
+}
+
+fieldset {
+  // Browsers set a default `min-width: min-content;` on fieldsets,
+  // unlike e.g. `<div>`s, which have `min-width: 0;` by default.
+  // So we reset that to ensure fieldsets behave more like a standard block element.
+  // See https://github.com/twbs/bootstrap/issues/12359
+  // and https://html.spec.whatwg.org/multipage/#the-fieldset-and-legend-elements
+  min-width: 0;
+  // Reset the default outline behavior of fieldsets so they don't affect page layout.
+  padding: 0;
+  margin: 0;
+  border: 0;
+}
+
+// 1. Correct the text wrapping in Edge and IE.
+// 2. Correct the color inheritance from `fieldset` elements in IE.
+legend {
+  display: block;
+  width: 100%;
+  max-width: 100%; // 1
+  padding: 0;
+  margin-bottom: .5rem;
+  @include font-size(1.5rem);
+  line-height: inherit;
+  color: inherit; // 2
+  white-space: normal; // 1
+}
+
+progress {
+  vertical-align: baseline; // Add the correct vertical alignment in Chrome, Firefox, and Opera.
+}
+
+// Correct the cursor style of increment and decrement buttons in Chrome.
+[type="number"]::-webkit-inner-spin-button,
+[type="number"]::-webkit-outer-spin-button {
+  height: auto;
+}
+
+[type="search"] {
+  // This overrides the extra rounded corners on search inputs in iOS so that our
+  // `.form-control` class can properly style them. Note that this cannot simply
+  // be added to `.form-control` as it's not specific enough. For details, see
+  // https://github.com/twbs/bootstrap/issues/11586.
+  outline-offset: -2px; // 2. Correct the outline style in Safari.
+  -webkit-appearance: none;
+}
+
+//
+// Remove the inner padding in Chrome and Safari on macOS.
+//
+
+[type="search"]::-webkit-search-decoration {
+  -webkit-appearance: none;
+}
+
+//
+// 1. Correct the inability to style clickable types in iOS and Safari.
+// 2. Change font properties to `inherit` in Safari.
+//
+
+::-webkit-file-upload-button {
+  font: inherit; // 2
+  -webkit-appearance: button; // 1
+}
+
+//
+// Correct element displays
+//
+
+output {
+  display: inline-block;
+}
+
+summary {
+  display: list-item; // Add the correct display in all browsers
+  cursor: pointer;
+}
+
+template {
+  display: none; // Add the correct display in IE
+}
+
+// Always hide an element with the `hidden` HTML attribute (from PureCSS).
+// Needed for proper display in IE 10-.
+[hidden] {
+  display: none !important;
+}

example/static/vendor/bootstrap/scss/_root.scss

@@ -0,0 +1,19 @@
+:root {
+  // Custom variable values only support SassScript inside `#{}`.
+  @each $color, $value in $colors {
+    --#{$color}: #{$value};
+  }
+
+  @each $color, $value in $theme-colors {
+    --#{$color}: #{$value};
+  }
+
+  @each $bp, $value in $grid-breakpoints {
+    --breakpoint-#{$bp}: #{$value};
+  }
+
+  // Use `inspect` for lists so that quoted items keep the quotes.
+  // See https://github.com/sass/sass/issues/2383#issuecomment-336349172
+  --font-family-sans-serif: #{inspect($font-family-sans-serif)};
+  --font-family-monospace: #{inspect($font-family-monospace)};
+}

example/static/vendor/bootstrap/scss/_spinners.scss

@@ -0,0 +1,55 @@
+//
+// Rotating border
+//
+
+@keyframes spinner-border {
+  to { transform: rotate(360deg); }
+}
+
+.spinner-border {
+  display: inline-block;
+  width: $spinner-width;
+  height: $spinner-height;
+  vertical-align: text-bottom;
+  border: $spinner-border-width solid currentColor;
+  border-right-color: transparent;
+  // stylelint-disable-next-line property-blacklist
+  border-radius: 50%;
+  animation: spinner-border .75s linear infinite;
+}
+
+.spinner-border-sm {
+  width: $spinner-width-sm;
+  height: $spinner-height-sm;
+  border-width: $spinner-border-width-sm;
+}
+
+//
+// Growing circle
+//
+
+@keyframes spinner-grow {
+  0% {
+    transform: scale(0);
+  }
+  50% {
+    opacity: 1;
+  }
+}
+
+.spinner-grow {
+  display: inline-block;
+  width: $spinner-width;
+  height: $spinner-height;
+  vertical-align: text-bottom;
+  background-color: currentColor;
+  // stylelint-disable-next-line property-blacklist
+  border-radius: 50%;
+  opacity: 0;
+  animation: spinner-grow .75s linear infinite;
+}
+
+.spinner-grow-sm {
+  width: $spinner-width-sm;
+  height: $spinner-height-sm;
+}

example/static/vendor/bootstrap/scss/_tables.scss

@@ -0,0 +1,185 @@
+//
+// Basic Bootstrap table
+//
+
+.table {
+  width: 100%;
+  margin-bottom: $spacer;
+  color: $table-color;
+  background-color: $table-bg; // Reset for nesting within parents with `background-color`.
+
+  th,
+  td {
+    padding: $table-cell-padding;
+    vertical-align: top;
+    border-top: $table-border-width solid $table-border-color;
+  }
+
+  thead th {
+    vertical-align: bottom;
+    border-bottom: (2 * $table-border-width) solid $table-border-color;
+  }
+
+  tbody + tbody {
+    border-top: (2 * $table-border-width) solid $table-border-color;
+  }
+}
+
+
+//
+// Condensed table w/ half padding
+//
+
+.table-sm {
+  th,
+  td {
+    padding: $table-cell-padding-sm;
+  }
+}
+
+
+// Border versions
+//
+// Add or remove borders all around the table and between all the columns.
+
+.table-bordered {
+  border: $table-border-width solid $table-border-color;
+
+  th,
+  td {
+    border: $table-border-width solid $table-border-color;
+  }
+
+  thead {
+    th,
+    td {
+      border-bottom-width: 2 * $table-border-width;
+    }
+  }
+}
+
+.table-borderless {
+  th,
+  td,
+  thead th,
+  tbody + tbody {
+    border: 0;
+  }
+}
+
+// Zebra-striping
+//
+// Default zebra-stripe styles (alternating gray and transparent backgrounds)
+
+.table-striped {
+  tbody tr:nth-of-type(#{$table-striped-order}) {
+    background-color: $table-accent-bg;
+  }
+}
+
+
+// Hover effect
+//
+// Placed here since it has to come after the potential zebra striping
+
+.table-hover {
+  tbody tr {
+    @include hover {
+      color: $table-hover-color;
+      background-color: $table-hover-bg;
+    }
+  }
+}
+
+
+// Table backgrounds
+//
+// Exact selectors below required to override `.table-striped` and prevent
+// inheritance to nested tables.
+
+@each $color, $value in $theme-colors {
+  @include table-row-variant($color, theme-color-level($color, $table-bg-level), theme-color-level($color, $table-border-level));
+}
+
+@include table-row-variant(active, $table-active-bg);
+
+
+// Dark styles
+//
+// Same table markup, but inverted color scheme: dark background and light text.
+
+// stylelint-disable-next-line no-duplicate-selectors
+.table {
+  .thead-dark {
+    th {
+      color: $table-dark-color;
+      background-color: $table-dark-bg;
+      border-color: $table-dark-border-color;
+    }
+  }
+
+  .thead-light {
+    th {
+      color: $table-head-color;
+      background-color: $table-head-bg;
+      border-color: $table-border-color;
+    }
+  }
+}
+
+.table-dark {
+  color: $table-dark-color;
+  background-color: $table-dark-bg;
+
+  th,
+  td,
+  thead th {
+    border-color: $table-dark-border-color;
+  }
+
+  &.table-bordered {
+    border: 0;
+  }
+
+  &.table-striped {
+    tbody tr:nth-of-type(odd) {
+      background-color: $table-dark-accent-bg;
+    }
+  }
+
+  &.table-hover {
+    tbody tr {
+      @include hover {
+        color: $table-dark-hover-color;
+        background-color: $table-dark-hover-bg;
+      }
+    }
+  }
+}
+
+
+// Responsive tables
+//
+// Generate series of `.table-responsive-*` classes for configuring the screen
+// size of where your table will overflow.
+
+.table-responsive {
+  @each $breakpoint in map-keys($grid-breakpoints) {
+    $next: breakpoint-next($breakpoint, $grid-breakpoints);
+    $infix: breakpoint-infix($next, $grid-breakpoints);
+
+    &#{$infix} {
+      @include media-breakpoint-down($breakpoint) {
+        display: block;
+        width: 100%;
+        overflow-x: auto;
+        -webkit-overflow-scrolling: touch;
+
+        // Prevent double border on horizontal scroll due to use of `display: block;`
+        > .table-bordered {
+          border: 0;
+        }
+      }
+    }
+  }
+}

example/static/vendor/bootstrap/scss/_toasts.scss

@@ -0,0 +1,44 @@
+.toast {
+  max-width: $toast-max-width;
+  overflow: hidden; // cheap rounded corners on nested items
+  @include font-size($toast-font-size);
+  color: $toast-color;
+  background-color: $toast-background-color;
+  background-clip: padding-box;
+  border: $toast-border-width solid $toast-border-color;
+  box-shadow: $toast-box-shadow;
+  backdrop-filter: blur(10px);
+  opacity: 0;
+  @include border-radius($toast-border-radius);
+
+  &:not(:last-child) {
+    margin-bottom: $toast-padding-x;
+  }
+
+  &.showing {
+    opacity: 1;
+  }
+
+  &.show {
+    display: block;
+    opacity: 1;
+  }
+
+  &.hide {
+    display: none;
+  }
+}
+
+.toast-header {
+  display: flex;
+  align-items: center;
+  padding: $toast-padding-y $toast-padding-x;
+  color: $toast-header-color;
+  background-color: $toast-header-background-color;
+  background-clip: padding-box;
+  border-bottom: $toast-border-width solid $toast-header-border-color;
+}
+
+.toast-body {
+  padding: $toast-padding-x; // apply to both vertical and horizontal
+}

example/static/vendor/bootstrap/scss/_tooltip.scss

@@ -0,0 +1,115 @@
+// Base class
+.tooltip {
+  position: absolute;
+  z-index: $zindex-tooltip;
+  display: block;
+  margin: $tooltip-margin;
+  // Our parent element can be arbitrary since tooltips are by default inserted as a sibling of their target element.
+  // So reset our font and text properties to avoid inheriting weird values.
+  @include reset-text();
+  @include font-size($tooltip-font-size);
+  // Allow breaking very long words so they don't overflow the tooltip's bounds
+  word-wrap: break-word;
+  opacity: 0;
+
+  &.show { opacity: $tooltip-opacity; }
+
+  .arrow {
+    position: absolute;
+    display: block;
+    width: $tooltip-arrow-width;
+    height: $tooltip-arrow-height;
+
+    &::before {
+      position: absolute;
+      content: "";
+      border-color: transparent;
+      border-style: solid;
+    }
+  }
+}
+
+.bs-tooltip-top {
+  padding: $tooltip-arrow-height 0;
+
+  .arrow {
+    bottom: 0;
+
+    &::before {
+      top: 0;
+      border-width: $tooltip-arrow-height ($tooltip-arrow-width / 2) 0;
+      border-top-color: $tooltip-arrow-color;
+    }
+  }
+}
+
+.bs-tooltip-right {
+  padding: 0 $tooltip-arrow-height;
+
+  .arrow {
+    left: 0;
+    width: $tooltip-arrow-height;
+    height: $tooltip-arrow-width;
+
+    &::before {
+      right: 0;
+      border-width: ($tooltip-arrow-width / 2) $tooltip-arrow-height ($tooltip-arrow-width / 2) 0;
+      border-right-color: $tooltip-arrow-color;
+    }
+  }
+}
+
+.bs-tooltip-bottom {
+  padding: $tooltip-arrow-height 0;
+
+  .arrow {
+    top: 0;
+
+    &::before {
+      bottom: 0;
+      border-width: 0 ($tooltip-arrow-width / 2) $tooltip-arrow-height;
+      border-bottom-color: $tooltip-arrow-color;
+    }
+  }
+}
+
+.bs-tooltip-left {
+  padding: 0 $tooltip-arrow-height;
+
+  .arrow {
+    right: 0;
+    width: $tooltip-arrow-height;
+    height: $tooltip-arrow-width;
+
+    &::before {
+      left: 0;
+      border-width: ($tooltip-arrow-width / 2) 0 ($tooltip-arrow-width / 2) $tooltip-arrow-height;
+      border-left-color: $tooltip-arrow-color;
+    }
+  }
+}
+
+.bs-tooltip-auto {
+  &[x-placement^="top"] {
+    @extend .bs-tooltip-top;
+  }
+  &[x-placement^="right"] {
+    @extend .bs-tooltip-right;
+  }
+  &[x-placement^="bottom"] {
+    @extend .bs-tooltip-bottom;
+  }
+  &[x-placement^="left"] {
+    @extend .bs-tooltip-left;
+  }
+}
+
+// Wrapper for the tooltip content
+.tooltip-inner {
+  max-width: $tooltip-max-width;
+  padding: $tooltip-padding-y $tooltip-padding-x;
+  color: $tooltip-color;
+  text-align: center;
+  background-color: $tooltip-bg;
+  @include border-radius($tooltip-border-radius);
+}

example/static/vendor/bootstrap/scss/_transitions.scss

@@ -0,0 +1,20 @@
+.fade {
+  @include transition($transition-fade);
+
+  &:not(.show) {
+    opacity: 0;
+  }
+}
+
+.collapse {
+  &:not(.show) {
+    display: none;
+  }
+}
+
+.collapsing {
+  position: relative;
+  height: 0;
+  overflow: hidden;
+  @include transition($transition-collapse);
+}

example/static/vendor/bootstrap/scss/_type.scss

@@ -0,0 +1,125 @@
+// stylelint-disable declaration-no-important, selector-list-comma-newline-after
+
+//
+// Headings
+//
+
+h1, h2, h3, h4, h5, h6,
+.h1, .h2, .h3, .h4, .h5, .h6 {
+  margin-bottom: $headings-margin-bottom;
+  font-family: $headings-font-family;
+  font-weight: $headings-font-weight;
+  line-height: $headings-line-height;
+  color: $headings-color;
+}
+
+h1, .h1 { @include font-size($h1-font-size); }
+h2, .h2 { @include font-size($h2-font-size); }
+h3, .h3 { @include font-size($h3-font-size); }
+h4, .h4 { @include font-size($h4-font-size); }
+h5, .h5 { @include font-size($h5-font-size); }
+h6, .h6 { @include font-size($h6-font-size); }
+
+.lead {
+  @include font-size($lead-font-size);
+  font-weight: $lead-font-weight;
+}
+
+// Type display classes
+.display-1 {
+  @include font-size($display1-size);
+  font-weight: $display1-weight;
+  line-height: $display-line-height;
+}
+.display-2 {
+  @include font-size($display2-size);
+  font-weight: $display2-weight;
+  line-height: $display-line-height;
+}
+.display-3 {
+  @include font-size($display3-size);
+  font-weight: $display3-weight;
+  line-height: $display-line-height;
+}
+.display-4 {
+  @include font-size($display4-size);
+  font-weight: $display4-weight;
+  line-height: $display-line-height;
+}
+
+
+//
+// Horizontal rules
+//
+
+hr {
+  margin-top: $hr-margin-y;
+  margin-bottom: $hr-margin-y;
+  border: 0;
+  border-top: $hr-border-width solid $hr-border-color;
+}
+
+
+//
+// Emphasis
+//
+
+small,
+.small {
+  @include font-size($small-font-size);
+  font-weight: $font-weight-normal;
+}
+
+mark,
+.mark {
+  padding: $mark-padding;
+  background-color: $mark-bg;
+}
+
+
+//
+// Lists
+//
+
+.list-unstyled {
+  @include list-unstyled;
+}
+
+// Inline turns list items into inline-block
+.list-inline {
+  @include list-unstyled;
+}
+.list-inline-item {
+  display: inline-block;
+
+  &:not(:last-child) {
+    margin-right: $list-inline-padding;
+  }
+}
+
+
+//
+// Misc
+//
+
+// Builds on `abbr`
+.initialism {
+  @include font-size(90%);
+  text-transform: uppercase;
+}
+
+// Blockquotes
+.blockquote {
+  margin-bottom: $spacer;
+  @include font-size($blockquote-font-size);
+}
+
+.blockquote-footer {
+  display: block;
+  @include font-size($blockquote-small-font-size);
+  color: $blockquote-small-color;
+
+  &::before {
+    content: "\2014\00A0"; // em dash, nbsp
+  }
+}

example/static/vendor/bootstrap/scss/_utilities.scss

@@ -0,0 +1,17 @@
+@import "utilities/align";
+@import "utilities/background";
+@import "utilities/borders";
+@import "utilities/clearfix";
+@import "utilities/display";
+@import "utilities/embed";
+@import "utilities/flex";
+@import "utilities/float";
+@import "utilities/overflow";
+@import "utilities/position";
+@import "utilities/screenreaders";
+@import "utilities/shadows";
+@import "utilities/sizing";
+@import "utilities/stretched-link";
+@import "utilities/spacing";
+@import "utilities/text";
+@import "utilities/visibility";

example/static/vendor/bootstrap/scss/bootstrap-grid.scss

@@ -0,0 +1,29 @@
+/*!
+ * Bootstrap Grid v4.3.1 (https://getbootstrap.com/)
+ * Copyright 2011-2019 The Bootstrap Authors
+ * Copyright 2011-2019 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ */
+
+html {
+  box-sizing: border-box;
+  -ms-overflow-style: scrollbar;
+}
+
+*,
+*::before,
+*::after {
+  box-sizing: inherit;
+}
+
+@import "functions";
+@import "variables";
+
+@import "mixins/breakpoints";
+@import "mixins/grid-framework";
+@import "mixins/grid";
+
+@import "grid";
+@import "utilities/display";
+@import "utilities/flex";
+@import "utilities/spacing";

example/static/vendor/bootstrap/scss/bootstrap-reboot.scss

@@ -0,0 +1,12 @@
+/*!
+ * Bootstrap Reboot v4.3.1 (https://getbootstrap.com/)
+ * Copyright 2011-2019 The Bootstrap Authors
+ * Copyright 2011-2019 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ * Forked from Normalize.css, licensed MIT (https://github.com/necolas/normalize.css/blob/master/LICENSE.md)
+ */
+
+@import "functions";
+@import "variables";
+@import "mixins";
+@import "reboot";

example/static/vendor/bootstrap/scss/bootstrap.scss

@@ -0,0 +1,44 @@
+/*!
+ * Bootstrap v4.3.1 (https://getbootstrap.com/)
+ * Copyright 2011-2019 The Bootstrap Authors
+ * Copyright 2011-2019 Twitter, Inc.
+ * Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+ */
+
+@import "functions";
+@import "variables";
+@import "mixins";
+@import "root";
+@import "reboot";
+@import "type";
+@import "images";
+@import "code";
+@import "grid";
+@import "tables";
+@import "forms";
+@import "buttons";
+@import "transitions";
+@import "dropdown";
+@import "button-group";
+@import "input-group";
+@import "custom-forms";
+@import "nav";
+@import "navbar";
+@import "card";
+@import "breadcrumb";
+@import "pagination";
+@import "badge";
+@import "jumbotron";
+@import "alert";
+@import "progress";
+@import "media";
+@import "list-group";
+@import "close";
+@import "toasts";
+@import "modal";
+@import "tooltip";
+@import "popover";
+@import "carousel";
+@import "spinners";
+@import "utilities";
+@import "print";

example/static/vendor/bootstrap/scss/mixins/_alert.scss

@@ -0,0 +1,13 @@
+@mixin alert-variant($background, $border, $color) {
+  color: $color;
+  @include gradient-bg($background);
+  border-color: $border;
+
+  hr {
+    border-top-color: darken($border, 5%);
+  }
+
+  .alert-link {
+    color: darken($color, 10%);
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_background-variant.scss

@@ -0,0 +1,21 @@
+// stylelint-disable declaration-no-important
+
+// Contextual backgrounds
+
+@mixin bg-variant($parent, $color) {
+  #{$parent} {
+    background-color: $color !important;
+  }
+  a#{$parent},
+  button#{$parent} {
+    @include hover-focus {
+      background-color: darken($color, 10%) !important;
+    }
+  }
+}
+
+@mixin bg-gradient-variant($parent, $color) {
+  #{$parent} {
+    background: $color linear-gradient(180deg, mix($body-bg, $color, 15%), $color) repeat-x !important;
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_badge.scss

@@ -0,0 +1,17 @@
+@mixin badge-variant($bg) {
+  color: color-yiq($bg);
+  background-color: $bg;
+
+  @at-root a#{&} {
+    @include hover-focus {
+      color: color-yiq($bg);
+      background-color: darken($bg, 10%);
+    }
+
+    &:focus,
+    &.focus {
+      outline: 0;
+      box-shadow: 0 0 0 $badge-focus-width rgba($bg, .5);
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_border-radius.scss

@@ -0,0 +1,63 @@
+// stylelint-disable property-blacklist
+// Single side border-radius
+
+@mixin border-radius($radius: $border-radius, $fallback-border-radius: false) {
+  @if $enable-rounded {
+    border-radius: $radius;
+  }
+  @else if $fallback-border-radius != false {
+    border-radius: $fallback-border-radius;
+  }
+}
+
+@mixin border-top-radius($radius) {
+  @if $enable-rounded {
+    border-top-left-radius: $radius;
+    border-top-right-radius: $radius;
+  }
+}
+
+@mixin border-right-radius($radius) {
+  @if $enable-rounded {
+    border-top-right-radius: $radius;
+    border-bottom-right-radius: $radius;
+  }
+}
+
+@mixin border-bottom-radius($radius) {
+  @if $enable-rounded {
+    border-bottom-right-radius: $radius;
+    border-bottom-left-radius: $radius;
+  }
+}
+
+@mixin border-left-radius($radius) {
+  @if $enable-rounded {
+    border-top-left-radius: $radius;
+    border-bottom-left-radius: $radius;
+  }
+}
+
+@mixin border-top-left-radius($radius) {
+  @if $enable-rounded {
+    border-top-left-radius: $radius;
+  }
+}
+
+@mixin border-top-right-radius($radius) {
+  @if $enable-rounded {
+    border-top-right-radius: $radius;
+  }
+}
+
+@mixin border-bottom-right-radius($radius) {
+  @if $enable-rounded {
+    border-bottom-right-radius: $radius;
+  }
+}
+
+@mixin border-bottom-left-radius($radius) {
+  @if $enable-rounded {
+    border-bottom-left-radius: $radius;
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_box-shadow.scss

@@ -0,0 +1,20 @@
+@mixin box-shadow($shadow...) {
+  @if $enable-shadows {
+    $result: ();
+
+    @if (length($shadow) == 1) {
+      // We can pass `@include box-shadow(none);`
+      $result: $shadow;
+    } @else {
+      // Filter to avoid invalid properties for example `box-shadow: none, 1px 1px black;`
+      @for $i from 1 through length($shadow) {
+        @if nth($shadow, $i) != "none" {
+          $result: append($result, nth($shadow, $i), "comma");
+        }
+      }
+    }
+    @if (length($result) > 0) {
+      box-shadow: $result;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_breakpoints.scss

@@ -0,0 +1,123 @@
+// Breakpoint viewport sizes and media queries.
+//
+// Breakpoints are defined as a map of (name: minimum width), order from small to large:
+//
+//    (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px)
+//
+// The map defined in the `$grid-breakpoints` global variable is used as the `$breakpoints` argument by default.
+
+// Name of the next breakpoint, or null for the last breakpoint.
+//
+//    >> breakpoint-next(sm)
+//    md
+//    >> breakpoint-next(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
+//    md
+//    >> breakpoint-next(sm, $breakpoint-names: (xs sm md lg xl))
+//    md
+@function breakpoint-next($name, $breakpoints: $grid-breakpoints, $breakpoint-names: map-keys($breakpoints)) {
+  $n: index($breakpoint-names, $name);
+  @return if($n != null and $n < length($breakpoint-names), nth($breakpoint-names, $n + 1), null);
+}
+
+// Minimum breakpoint width. Null for the smallest (first) breakpoint.
+//
+//    >> breakpoint-min(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
+//    576px
+@function breakpoint-min($name, $breakpoints: $grid-breakpoints) {
+  $min: map-get($breakpoints, $name);
+  @return if($min != 0, $min, null);
+}
+
+// Maximum breakpoint width. Null for the largest (last) breakpoint.
+// The maximum value is calculated as the minimum of the next one less 0.02px
+// to work around the limitations of `min-` and `max-` prefixes and viewports with fractional widths.
+// See https://www.w3.org/TR/mediaqueries-4/#mq-min-max
+// Uses 0.02px rather than 0.01px to work around a current rounding bug in Safari.
+// See https://bugs.webkit.org/show_bug.cgi?id=178261
+//
+//    >> breakpoint-max(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
+//    767.98px
+@function breakpoint-max($name, $breakpoints: $grid-breakpoints) {
+  $next: breakpoint-next($name, $breakpoints);
+  @return if($next, breakpoint-min($next, $breakpoints) - .02, null);
+}
+
+// Returns a blank string if smallest breakpoint, otherwise returns the name with a dash in front.
+// Useful for making responsive utilities.
+//
+//    >> breakpoint-infix(xs, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
+//    ""  (Returns a blank string)
+//    >> breakpoint-infix(sm, (xs: 0, sm: 576px, md: 768px, lg: 992px, xl: 1200px))
+//    "-sm"
+@function breakpoint-infix($name, $breakpoints: $grid-breakpoints) {
+  @return if(breakpoint-min($name, $breakpoints) == null, "", "-#{$name}");
+}
+
+// Media of at least the minimum breakpoint width. No query for the smallest breakpoint.
+// Makes the @content apply to the given breakpoint and wider.
+@mixin media-breakpoint-up($name, $breakpoints: $grid-breakpoints) {
+  $min: breakpoint-min($name, $breakpoints);
+  @if $min {
+    @media (min-width: $min) {
+      @content;
+    }
+  } @else {
+    @content;
+  }
+}
+
+// Media of at most the maximum breakpoint width. No query for the largest breakpoint.
+// Makes the @content apply to the given breakpoint and narrower.
+@mixin media-breakpoint-down($name, $breakpoints: $grid-breakpoints) {
+  $max: breakpoint-max($name, $breakpoints);
+  @if $max {
+    @media (max-width: $max) {
+      @content;
+    }
+  } @else {
+    @content;
+  }
+}
+
+// Media that spans multiple breakpoint widths.
+// Makes the @content apply between the min and max breakpoints
+@mixin media-breakpoint-between($lower, $upper, $breakpoints: $grid-breakpoints) {
+  $min: breakpoint-min($lower, $breakpoints);
+  $max: breakpoint-max($upper, $breakpoints);
+
+  @if $min != null and $max != null {
+    @media (min-width: $min) and (max-width: $max) {
+      @content;
+    }
+  } @else if $max == null {
+    @include media-breakpoint-up($lower, $breakpoints) {
+      @content;
+    }
+  } @else if $min == null {
+    @include media-breakpoint-down($upper, $breakpoints) {
+      @content;
+    }
+  }
+}
+
+// Media between the breakpoint's minimum and maximum widths.
+// No minimum for the smallest breakpoint, and no maximum for the largest one.
+// Makes the @content apply only to the given breakpoint, not viewports any wider or narrower.
+@mixin media-breakpoint-only($name, $breakpoints: $grid-breakpoints) {
+  $min: breakpoint-min($name, $breakpoints);
+  $max: breakpoint-max($name, $breakpoints);
+
+  @if $min != null and $max != null {
+    @media (min-width: $min) and (max-width: $max) {
+      @content;
+    }
+  } @else if $max == null {
+    @include media-breakpoint-up($name, $breakpoints) {
+      @content;
+    }
+  } @else if $min == null {
+    @include media-breakpoint-down($name, $breakpoints) {
+      @content;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_buttons.scss

@@ -0,0 +1,107 @@
+// Button variants
+//
+// Easily pump out default styles, as well as :hover, :focus, :active,
+// and disabled options for all buttons
+
+@mixin button-variant($background, $border, $hover-background: darken($background, 7.5%), $hover-border: darken($border, 10%), $active-background: darken($background, 10%), $active-border: darken($border, 12.5%)) {
+  color: color-yiq($background);
+  @include gradient-bg($background);
+  border-color: $border;
+  @include box-shadow($btn-box-shadow);
+
+  @include hover {
+    color: color-yiq($hover-background);
+    @include gradient-bg($hover-background);
+    border-color: $hover-border;
+  }
+
+  &:focus,
+  &.focus {
+    // Avoid using mixin so we can pass custom focus shadow properly
+    @if $enable-shadows {
+      box-shadow: $btn-box-shadow, 0 0 0 $btn-focus-width rgba(mix(color-yiq($background), $border, 15%), .5);
+    } @else {
+      box-shadow: 0 0 0 $btn-focus-width rgba(mix(color-yiq($background), $border, 15%), .5);
+    }
+  }
+
+  // Disabled comes first so active can properly restyle
+  &.disabled,
+  &:disabled {
+    color: color-yiq($background);
+    background-color: $background;
+    border-color: $border;
+    // Remove CSS gradients if they're enabled
+    @if $enable-gradients {
+      background-image: none;
+    }
+  }
+
+  &:not(:disabled):not(.disabled):active,
+  &:not(:disabled):not(.disabled).active,
+  .show > &.dropdown-toggle {
+    color: color-yiq($active-background);
+    background-color: $active-background;
+    @if $enable-gradients {
+      background-image: none; // Remove the gradient for the pressed/active state
+    }
+    border-color: $active-border;
+
+    &:focus {
+      // Avoid using mixin so we can pass custom focus shadow properly
+      @if $enable-shadows and $btn-active-box-shadow != none {
+        box-shadow: $btn-active-box-shadow, 0 0 0 $btn-focus-width rgba(mix(color-yiq($background), $border, 15%), .5);
+      } @else {
+        box-shadow: 0 0 0 $btn-focus-width rgba(mix(color-yiq($background), $border, 15%), .5);
+      }
+    }
+  }
+}
+
+@mixin button-outline-variant($color, $color-hover: color-yiq($color), $active-background: $color, $active-border: $color) {
+  color: $color;
+  border-color: $color;
+
+  @include hover {
+    color: $color-hover;
+    background-color: $active-background;
+    border-color: $active-border;
+  }
+
+  &:focus,
+  &.focus {
+    box-shadow: 0 0 0 $btn-focus-width rgba($color, .5);
+  }
+
+  &.disabled,
+  &:disabled {
+    color: $color;
+    background-color: transparent;
+  }
+
+  &:not(:disabled):not(.disabled):active,
+  &:not(:disabled):not(.disabled).active,
+  .show > &.dropdown-toggle {
+    color: color-yiq($active-background);
+    background-color: $active-background;
+    border-color: $active-border;
+
+    &:focus {
+      // Avoid using mixin so we can pass custom focus shadow properly
+      @if $enable-shadows and $btn-active-box-shadow != none {
+        box-shadow: $btn-active-box-shadow, 0 0 0 $btn-focus-width rgba($color, .5);
+      } @else {
+        box-shadow: 0 0 0 $btn-focus-width rgba($color, .5);
+      }
+    }
+  }
+}
+
+// Button sizes
+@mixin button-size($padding-y, $padding-x, $font-size, $line-height, $border-radius) {
+  padding: $padding-y $padding-x;
+  @include font-size($font-size);
+  line-height: $line-height;
+  // Manually declare to provide an override to the browser default
+  @include border-radius($border-radius, 0);
+}

example/static/vendor/bootstrap/scss/mixins/_caret.scss

@@ -0,0 +1,62 @@
+@mixin caret-down {
+  border-top: $caret-width solid;
+  border-right: $caret-width solid transparent;
+  border-bottom: 0;
+  border-left: $caret-width solid transparent;
+}
+
+@mixin caret-up {
+  border-top: 0;
+  border-right: $caret-width solid transparent;
+  border-bottom: $caret-width solid;
+  border-left: $caret-width solid transparent;
+}
+
+@mixin caret-right {
+  border-top: $caret-width solid transparent;
+  border-right: 0;
+  border-bottom: $caret-width solid transparent;
+  border-left: $caret-width solid;
+}
+
+@mixin caret-left {
+  border-top: $caret-width solid transparent;
+  border-right: $caret-width solid;
+  border-bottom: $caret-width solid transparent;
+}
+
+@mixin caret($direction: down) {
+  @if $enable-caret {
+    &::after {
+      display: inline-block;
+      margin-left: $caret-spacing;
+      vertical-align: $caret-vertical-align;
+      content: "";
+      @if $direction == down {
+        @include caret-down;
+      } @else if $direction == up {
+        @include caret-up;
+      } @else if $direction == right {
+        @include caret-right;
+      }
+    }
+
+    @if $direction == left {
+      &::after {
+        display: none;
+      }
+
+      &::before {
+        display: inline-block;
+        margin-right: $caret-spacing;
+        vertical-align: $caret-vertical-align;
+        content: "";
+        @include caret-left;
+      }
+    }
+
+    &:empty::after {
+      margin-left: 0;
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_clearfix.scss

@@ -0,0 +1,7 @@
+@mixin clearfix() {
+  &::after {
+    display: block;
+    clear: both;
+    content: "";
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_deprecate.scss

@@ -0,0 +1,10 @@
+// Deprecate mixin
+//
+// This mixin can be used to deprecate mixins or functions.
+// `$enable-deprecation-messages` is a global variable, `$ignore-warning` is a variable that can be passed to
+// some deprecated mixins to suppress the warning (for example if the mixin is still be used in the current version of Bootstrap)
+@mixin deprecate($name, $deprecate-version, $remove-version, $ignore-warning: false) {
+  @if ($enable-deprecation-messages != false and $ignore-warning != true) {
+    @warn "#{$name} has been deprecated as of #{$deprecate-version}. It will be removed entirely in #{$remove-version}.";
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_float.scss

@@ -0,0 +1,14 @@
+// stylelint-disable declaration-no-important
+
+@mixin float-left {
+  float: left !important;
+  @include deprecate("The `float-left` mixin", "v4.3.0", "v5");
+}
+@mixin float-right {
+  float: right !important;
+  @include deprecate("The `float-right` mixin", "v4.3.0", "v5");
+}
+@mixin float-none {
+  float: none !important;
+  @include deprecate("The `float-none` mixin", "v4.3.0", "v5");
+}

example/static/vendor/bootstrap/scss/mixins/_forms.scss

@@ -0,0 +1,192 @@
+// Form control focus state
+//
+// Generate a customized focus state and for any input with the specified color,
+// which defaults to the `$input-focus-border-color` variable.
+//
+// We highly encourage you to not customize the default value, but instead use
+// this to tweak colors on an as-needed basis. This aesthetic change is based on
+// WebKit's default styles, but applicable to a wider range of browsers. Its
+// usability and accessibility should be taken into account with any change.
+//
+// Example usage: change the default blue border and shadow to white for better
+// contrast against a dark gray background.
+@mixin form-control-focus() {
+  &:focus {
+    color: $input-focus-color;
+    background-color: $input-focus-bg;
+    border-color: $input-focus-border-color;
+    outline: 0;
+    // Avoid using mixin so we can pass custom focus shadow properly
+    @if $enable-shadows {
+      box-shadow: $input-box-shadow, $input-focus-box-shadow;
+    } @else {
+      box-shadow: $input-focus-box-shadow;
+    }
+  }
+}
+
+
+@mixin form-validation-state($state, $color, $icon) {
+  .#{$state}-feedback {
+    display: none;
+    width: 100%;
+    margin-top: $form-feedback-margin-top;
+    @include font-size($form-feedback-font-size);
+    color: $color;
+  }
+
+  .#{$state}-tooltip {
+    position: absolute;
+    top: 100%;
+    z-index: 5;
+    display: none;
+    max-width: 100%; // Contain to parent when possible
+    padding: $form-feedback-tooltip-padding-y $form-feedback-tooltip-padding-x;
+    margin-top: .1rem;
+    @include font-size($form-feedback-tooltip-font-size);
+    line-height: $form-feedback-tooltip-line-height;
+    color: color-yiq($color);
+    background-color: rgba($color, $form-feedback-tooltip-opacity);
+    @include border-radius($form-feedback-tooltip-border-radius);
+  }
+
+  .form-control {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      border-color: $color;
+
+      @if $enable-validation-icons {
+        padding-right: $input-height-inner;
+        background-image: $icon;
+        background-repeat: no-repeat;
+        background-position: center right $input-height-inner-quarter;
+        background-size: $input-height-inner-half $input-height-inner-half;
+      }
+
+      &:focus {
+        border-color: $color;
+        box-shadow: 0 0 0 $input-focus-width rgba($color, .25);
+      }
+
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+    }
+  }
+
+  // stylelint-disable-next-line selector-no-qualifying-type
+  textarea.form-control {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      @if $enable-validation-icons {
+        padding-right: $input-height-inner;
+        background-position: top $input-height-inner-quarter right $input-height-inner-quarter;
+      }
+    }
+  }
+
+  .custom-select {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      border-color: $color;
+
+      @if $enable-validation-icons {
+        padding-right: $custom-select-feedback-icon-padding-right;
+        background: $custom-select-background, $icon $custom-select-bg no-repeat $custom-select-feedback-icon-position / $custom-select-feedback-icon-size;
+      }
+
+      &:focus {
+        border-color: $color;
+        box-shadow: 0 0 0 $input-focus-width rgba($color, .25);
+      }
+
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+    }
+  }
+
+
+  .form-control-file {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+    }
+  }
+
+  .form-check-input {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      ~ .form-check-label {
+        color: $color;
+      }
+
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+    }
+  }
+
+  .custom-control-input {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      ~ .custom-control-label {
+        color: $color;
+
+        &::before {
+          border-color: $color;
+        }
+      }
+
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+
+      &:checked {
+        ~ .custom-control-label::before {
+          border-color: lighten($color, 10%);
+          @include gradient-bg(lighten($color, 10%));
+        }
+      }
+
+      &:focus {
+        ~ .custom-control-label::before {
+          box-shadow: 0 0 0 $input-focus-width rgba($color, .25);
+        }
+
+        &:not(:checked) ~ .custom-control-label::before {
+          border-color: $color;
+        }
+      }
+    }
+  }
+
+  // custom file
+  .custom-file-input {
+    .was-validated &:#{$state},
+    &.is-#{$state} {
+      ~ .custom-file-label {
+        border-color: $color;
+      }
+
+      ~ .#{$state}-feedback,
+      ~ .#{$state}-tooltip {
+        display: block;
+      }
+
+      &:focus {
+        ~ .custom-file-label {
+          border-color: $color;
+          box-shadow: 0 0 0 $input-focus-width rgba($color, .25);
+        }
+      }
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_gradients.scss

@@ -0,0 +1,45 @@
+// Gradients
+
+@mixin gradient-bg($color) {
+  @if $enable-gradients {
+    background: $color linear-gradient(180deg, mix($body-bg, $color, 15%), $color) repeat-x;
+  } @else {
+    background-color: $color;
+  }
+}
+
+// Horizontal gradient, from left to right
+//
+// Creates two color stops, start and end, by specifying a color and position for each color stop.
+@mixin gradient-x($start-color: $gray-700, $end-color: $gray-800, $start-percent: 0%, $end-percent: 100%) {
+  background-image: linear-gradient(to right, $start-color $start-percent, $end-color $end-percent);
+  background-repeat: repeat-x;
+}
+
+// Vertical gradient, from top to bottom
+//
+// Creates two color stops, start and end, by specifying a color and position for each color stop.
+@mixin gradient-y($start-color: $gray-700, $end-color: $gray-800, $start-percent: 0%, $end-percent: 100%) {
+  background-image: linear-gradient(to bottom, $start-color $start-percent, $end-color $end-percent);
+  background-repeat: repeat-x;
+}
+
+@mixin gradient-directional($start-color: $gray-700, $end-color: $gray-800, $deg: 45deg) {
+  background-image: linear-gradient($deg, $start-color, $end-color);
+  background-repeat: repeat-x;
+}
+@mixin gradient-x-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
+  background-image: linear-gradient(to right, $start-color, $mid-color $color-stop, $end-color);
+  background-repeat: no-repeat;
+}
+@mixin gradient-y-three-colors($start-color: $blue, $mid-color: $purple, $color-stop: 50%, $end-color: $red) {
+  background-image: linear-gradient($start-color, $mid-color $color-stop, $end-color);
+  background-repeat: no-repeat;
+}
+@mixin gradient-radial($inner-color: $gray-700, $outer-color: $gray-800) {
+  background-image: radial-gradient(circle, $inner-color, $outer-color);
+  background-repeat: no-repeat;
+}
+@mixin gradient-striped($color: rgba($white, .15), $angle: 45deg) {
+  background-image: linear-gradient($angle, $color 25%, transparent 25%, transparent 50%, $color 50%, $color 75%, transparent 75%, transparent);
+}

example/static/vendor/bootstrap/scss/mixins/_grid-framework.scss

@@ -0,0 +1,66 @@
+// Framework grid generation
+//
+// Used only by Bootstrap to generate the correct number of grid classes given
+// any value of `$grid-columns`.
+
+@mixin make-grid-columns($columns: $grid-columns, $gutter: $grid-gutter-width, $breakpoints: $grid-breakpoints) {
+  // Common properties for all breakpoints
+  %grid-column {
+    position: relative;
+    width: 100%;
+    padding-right: $gutter / 2;
+    padding-left: $gutter / 2;
+  }
+
+  @each $breakpoint in map-keys($breakpoints) {
+    $infix: breakpoint-infix($breakpoint, $breakpoints);
+
+    // Allow columns to stretch full width below their breakpoints
+    @for $i from 1 through $columns {
+      .col#{$infix}-#{$i} {
+        @extend %grid-column;
+      }
+    }
+    .col#{$infix},
+    .col#{$infix}-auto {
+      @extend %grid-column;
+    }
+
+    @include media-breakpoint-up($breakpoint, $breakpoints) {
+      // Provide basic `.col-{bp}` classes for equal-width flexbox columns
+      .col#{$infix} {
+        flex-basis: 0;
+        flex-grow: 1;
+        max-width: 100%;
+      }
+      .col#{$infix}-auto {
+        flex: 0 0 auto;
+        width: auto;
+        max-width: 100%; // Reset earlier grid tiers
+      }
+
+      @for $i from 1 through $columns {
+        .col#{$infix}-#{$i} {
+          @include make-col($i, $columns);
+        }
+      }
+
+      .order#{$infix}-first { order: -1; }
+
+      .order#{$infix}-last { order: $columns + 1; }
+
+      @for $i from 0 through $columns {
+        .order#{$infix}-#{$i} { order: $i; }
+      }
+
+      // `$columns - 1` because offsetting by the width of an entire row isn't possible
+      @for $i from 0 through ($columns - 1) {
+        @if not ($infix == "" and $i == 0) { // Avoid emitting useless .offset-0
+          .offset#{$infix}-#{$i} {
+            @include make-col-offset($i, $columns);
+          }
+        }
+      }
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_grid.scss

@@ -0,0 +1,51 @@
+/// Grid system
+//
+// Generate semantic grid columns with these mixins.
+
+@mixin make-container($gutter: $grid-gutter-width) {
+  width: 100%;
+  padding-right: $gutter / 2;
+  padding-left: $gutter / 2;
+  margin-right: auto;
+  margin-left: auto;
+}
+
+
+// For each breakpoint, define the maximum width of the container in a media query
+@mixin make-container-max-widths($max-widths: $container-max-widths, $breakpoints: $grid-breakpoints) {
+  @each $breakpoint, $container-max-width in $max-widths {
+    @include media-breakpoint-up($breakpoint, $breakpoints) {
+      max-width: $container-max-width;
+    }
+  }
+}
+
+@mixin make-row($gutter: $grid-gutter-width) {
+  display: flex;
+  flex-wrap: wrap;
+  margin-right: -$gutter / 2;
+  margin-left: -$gutter / 2;
+}
+
+@mixin make-col-ready($gutter: $grid-gutter-width) {
+  position: relative;
+  // Prevent columns from becoming too narrow when at smaller grid tiers by
+  // always setting `width: 100%;`. This works because we use `flex` values
+  // later on to override this initial width.
+  width: 100%;
+  padding-right: $gutter / 2;
+  padding-left: $gutter / 2;
+}
+
+@mixin make-col($size, $columns: $grid-columns) {
+  flex: 0 0 percentage($size / $columns);
+  // Add a `max-width` to ensure content within each column does not blow out
+  // the width of the column. Applies to IE10+ and Firefox. Chrome and Safari
+  // do not appear to require this.
+  max-width: percentage($size / $columns);
+}
+
+@mixin make-col-offset($size, $columns: $grid-columns) {
+  $num: $size / $columns;
+  margin-left: if($num == 0, 0, percentage($num));
+}

example/static/vendor/bootstrap/scss/mixins/_hover.scss

@@ -0,0 +1,37 @@
+// Hover mixin and `$enable-hover-media-query` are deprecated.
+//
+// Originally added during our alphas and maintained during betas, this mixin was
+// designed to prevent `:hover` stickiness on iOS-an issue where hover styles
+// would persist after initial touch.
+//
+// For backward compatibility, we've kept these mixins and updated them to
+// always return their regular pseudo-classes instead of a shimmed media query.
+//
+// Issue: https://github.com/twbs/bootstrap/issues/25195
+
+@mixin hover {
+  &:hover { @content; }
+}
+
+@mixin hover-focus {
+  &:hover,
+  &:focus {
+    @content;
+  }
+}
+
+@mixin plain-hover-focus {
+  &,
+  &:hover,
+  &:focus {
+    @content;
+  }
+}
+
+@mixin hover-focus-active {
+  &:hover,
+  &:focus,
+  &:active {
+    @content;
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_image.scss

@@ -0,0 +1,36 @@
+// Image Mixins
+// - Responsive image
+// - Retina image
+
+
+// Responsive image
+//
+// Keep images from scaling beyond the width of their parents.
+
+@mixin img-fluid {
+  // Part 1: Set a maximum relative to the parent
+  max-width: 100%;
+  // Part 2: Override the height to auto, otherwise images will be stretched
+  // when setting a width and height attribute on the img element.
+  height: auto;
+}
+
+
+// Retina image
+//
+// Short retina mixin for setting background-image and -size.
+
+@mixin img-retina($file-1x, $file-2x, $width-1x, $height-1x) {
+  background-image: url($file-1x);
+
+  // Autoprefixer takes care of adding -webkit-min-device-pixel-ratio and -o-min-device-pixel-ratio,
+  // but doesn't convert dppx=>dpi.
+  // There's no such thing as unprefixed min-device-pixel-ratio since it's nonstandard.
+  // Compatibility info: https://caniuse.com/#feat=css-media-resolution
+  @media only screen and (min-resolution: 192dpi), // IE9-11 don't support dppx
+    only screen and (min-resolution: 2dppx) { // Standardized
+    background-image: url($file-2x);
+    background-size: $width-1x $height-1x;
+  }
+  @include deprecate("`img-retina()`", "v4.3.0", "v5");
+}

example/static/vendor/bootstrap/scss/mixins/_list-group.scss

@@ -0,0 +1,21 @@
+// List Groups
+
+@mixin list-group-item-variant($state, $background, $color) {
+  .list-group-item-#{$state} {
+    color: $color;
+    background-color: $background;
+
+    &.list-group-item-action {
+      @include hover-focus {
+        color: $color;
+        background-color: darken($background, 5%);
+      }
+
+      &.active {
+        color: $white;
+        background-color: $color;
+        border-color: $color;
+      }
+    }
+  }
+}

example/static/vendor/bootstrap/scss/mixins/_lists.scss

@@ -0,0 +1,7 @@
+// Lists
+
+// Unstyled keeps list items block level, just removes default browser padding and list-style
+@mixin list-unstyled {
+  padding-left: 0;
+  list-style: none;
+}

example/static/vendor/bootstrap/scss/mixins/_nav-divider.scss

@@ -0,0 +1,10 @@
+// Horizontal dividers
+//
+// Dividers (basically an hr) within dropdowns and nav lists
+
+@mixin nav-divider($color: $nav-divider-color, $margin-y: $nav-divider-margin-y) {
+  height: 0;
+  margin: $margin-y 0;
+  overflow: hidden;
+  border-top: 1px solid $color;
+}