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diff --git a/docs/4.0/getting-started/accessibility.md b/docs/4.0/getting-started/accessibility.md
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@@ -0,0 +1,53 @@
+---
+layout: docs
+title: Accessibility
+description: A brief overview of Bootstrap's features and limitations for the creation of accessible content.
+group: getting-started
+toc: true
+---
+
+Bootstrap provides an easy-to-use framework of ready-made styles, layout tools, and interactive components, allowing developers to create web sites and applications that are visually appealing, functionally rich, and accessible out of the box.
+
+## Overview and limitations
+
+The overall accessibility of any project built with Bootstrap depends in large part on the author's markup, additional styling, and scripting they've included. However, provided that these have been implemented correctly, it should be perfectly possible to create web sites and applications with Bootstrap that fulfill [<abbr title="Web Content Accessibility Guidelines">WCAG</abbr> 2.0](https://www.w3.org/TR/WCAG20/) (A/AA/AAA), [Section 508](https://www.section508.gov/) and similar accessibility standards and requirements.
+
+### Structural markup
+
+Bootstrap's styling and layout can be applied to a wide range of markup structures. This documentation aims to provide developers with best practice examples to demonstrate the use of Bootstrap itself and illustrate appropriate semantic markup, including ways in which potential accessibility concerns can be addressed.
+
+### Interactive components
+
+Bootstrap's interactive components—such as modal dialogs, dropdown menus and custom tooltips—are designed to work for touch, mouse and keyboard users. Through the use of relevant [<abbr title="Web Accessibility Initiative">WAI</abbr> <abbr title="Accessible Rich Internet Applications">ARIA</abbr>](https://www.w3.org/WAI/intro/aria) roles and attributes, these components should also be understandable and operable using assistive technologies (such as screen readers).
+
+Because Bootstrap's components are purposely designed to be fairly generic, authors may need to include further <abbr title="Accessible Rich Internet Applications">ARIA</abbr> roles and attributes, as well as JavaScript behavior, to more accurately convey the precise nature and functionality of their component. This is usually noted in the documentation.
+
+### Color contrast
+
+Most colors that currently make up Bootstrap's default palette—used throughout the framework for things such as button variations, alert variations, form validation indicators—lead to *insufficient* color contrast (below the recommended [WCAG 2.0 color contrast ratio of 4.5:1](https://www.w3.org/TR/UNDERSTANDING-WCAG20/visual-audio-contrast-contrast.html)) when used against a light background. Authors will need to manually modify/extend these default colors to ensure adequate color contrast ratios.
+
+### Visually hidden content
+
+Content which should be visually hidden, but remain accessible to assistive technologies such as screen readers, can be styled using the `.sr-only` class. This can be useful in situations where additional visual information or cues (such as meaning denoted through the use of color) need to also be conveyed to non-visual users.
+
+{% highlight html %}
+<p class="text-danger">
+  <span class=".sr-only">Danger: </span>
+  This action is not reversible
+</p>
+{% endhighlight %}
+
+For visually hidden interactive controls, such as traditional "skip" links, `.sr-only` can be combined with the `.sr-only-focusable` class. This will ensure that the control becomes visible once focused (for sighted keyboard users).
+
+{% highlight html %}
+<a class="sr-only sr-only-focusable" href="#content">Skip to main content</a>
+{% endhighlight %}
+
+## Additional resources
+
+- [Web Content Accessibility Guidelines (WCAG) 2.0](https://www.w3.org/TR/WCAG20/)
+- [The A11Y Project](http://a11yproject.com/)
+- [MDN accessibility documentation](https://developer.mozilla.org/en-US/docs/Web/Accessibility)
+- [Tenon.io Accessibility Checker](https://tenon.io/)
+- [Colour Contrast Analyser (CCA)](https://www.paciellogroup.com/resources/contrastanalyser/)
+- ["HTML Codesniffer" bookmarklet for identifying accessibility issues](https://github.com/squizlabs/HTML_CodeSniffer)
diff --git a/docs/4.0/getting-started/best-practices.md b/docs/4.0/getting-started/best-practices.md
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+---
+layout: docs
+title: Best practices
+description: Learn about some of the best practices we've gathered from years of working on and using Bootstrap.
+group: getting-started
+---
+
+We've designed and developed Bootstrap to work in a number of environments. Here are some of the best practices we've gathered from years of working on and using it ourselves.
+
+{% callout info %}
+**Heads up!** This copy is a work in progress.
+{% endcallout %}
+
+### General outline
+- Working with CSS
+- Working with Sass files
+- Building new CSS components
+- Working with flexbox
+- Ask in [Slack](https://bootstrap-slack.herokuapp.com/)
diff --git a/docs/4.0/getting-started/browsers-devices.md b/docs/4.0/getting-started/browsers-devices.md
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--- /dev/null
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@@ -0,0 +1,196 @@
+---
+layout: docs
+title: Browsers and devices
+description: Learn about the browsers and devices, from modern to told, that are supported by Bootstrap, including known quirks and bugs for each.
+group: getting-started
+toc: true
+---
+
+## Supported browsers
+
+Bootstrap supports the **latest, stable releases** of all major browsers and platforms. On Windows, **we support Internet Explorer 10-11 / Microsoft Edge**.
+
+Alternative browsers which use the latest version of WebKit, Blink, or Gecko, whether directly or via the platform's web view API, are not explicitly supported. However, Bootstrap should (in most cases) display and function correctly in these browsers as well. More specific support information is provided below.
+
+### Mobile devices
+
+Generally speaking, Bootstrap supports the latest versions of each major platform's default browsers. Note that proxy browsers (such as Opera Mini, Opera Mobile's Turbo mode, UC Browser Mini, Amazon Silk) are not supported.
+
+<table class="table table-bordered table-striped table-responsive">
+  <thead>
+    <tr>
+      <td></td>
+      <th>Chrome</th>
+      <th>Firefox</th>
+      <th>Safari</th>
+      <th>Android Browser &amp; WebView</th>
+      <th>Microsoft Edge</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <th scope="row">Android</th>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-success">Android v5.0+ supported</td>
+      <td class="text-muted">N/A</td>
+    </tr>
+    <tr>
+      <th scope="row">iOS</th>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-muted">N/A</td>
+    </tr>
+    <tr>
+      <th scope="row">Windows 10 Mobile</th>
+      <td class="text-muted">N/A</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-success">Supported</td>
+    </tr>
+  </tbody>
+</table>
+
+### Desktop browsers
+
+Similarly, the latest versions of most desktop browsers are supported.
+
+<table class="table table-bordered table-striped table-responsive">
+  <thead>
+    <tr>
+      <td></td>
+      <th>Chrome</th>
+      <th>Firefox</th>
+      <th>Internet Explorer</th>
+      <th>Microsoft Edge</th>
+      <th>Opera</th>
+      <th>Safari</th>
+    </tr>
+  </thead>
+  <tbody>
+    <tr>
+      <th scope="row">Mac</th>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-muted">N/A</td>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+    </tr>
+    <tr>
+      <th scope="row">Windows</th>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported, IE10+</td>
+      <td class="text-success">Supported</td>
+      <td class="text-success">Supported</td>
+      <td class="text-danger">Not supported</td>
+    </tr>
+  </tbody>
+</table>
+
+For Firefox, in addition to the latest normal stable release, we also support the latest [Extended Support Release (ESR)](https://www.mozilla.org/en-US/firefox/organizations/faq/) version of Firefox.
+
+Unofficially, Bootstrap should look and behave well enough in Chromium and Chrome for Linux, Firefox for Linux, and Internet Explorer 9, though they are not officially supported.
+
+For a list of some of the browser bugs that Bootstrap has to grapple with, see our [Wall of browser bugs]({{ site.baseurl }}/browser-bugs/).
+
+## Internet Explorer
+
+Internet Explorer 10+ is supported; IE9 and down is not. Please be aware that some CSS3 properties and HTML5 elements are not fully supported in IE10, or require prefixed properties for full functionality. Visit [Can I use...](http://caniuse.com/) for details on browser support of CSS3 and HTML5 features.
+
+**If you require IE8-9 support, use Bootstrap 3.** It's the most stable version of our code and is still supported by our team for critical bugfixes and documentation changes. However, no new features will be added to it.
+
+## Internet Explorer 10 in Windows Phone 8
+
+Internet Explorer 10 in Windows Phone 8 versions older than [Update 3 (a.k.a. GDR3)](https://blogs.windows.com/buildingapps/2013/10/14/introducing-windows-phone-preview-for-developers/) doesn't differentiate **device width** from **viewport width** in `@-ms-viewport` at-rules, and thus doesn't properly apply the media queries in Bootstrap's CSS. To address this, you'll need to **include the following JavaScript to work around the bug**.
+
+{% highlight js %}
+// Copyright 2014-2017 The Bootstrap Authors
+// Copyright 2014-2017 Twitter, Inc.
+// Licensed under MIT (https://github.com/twbs/bootstrap/blob/master/LICENSE)
+if (navigator.userAgent.match(/IEMobile\/10\.0/)) {
+  var msViewportStyle = document.createElement('style')
+  msViewportStyle.appendChild(
+    document.createTextNode(
+      '@-ms-viewport{width:auto!important}'
+    )
+  )
+  document.head.appendChild(msViewportStyle)
+}
+{% endhighlight %}
+
+For more information and usage guidelines, read [Windows Phone 8 and Device-Width](https://timkadlec.com/2013/01/windows-phone-8-and-device-width/).
+
+As a heads up, we include this in all of Bootstrap's documentation and examples as a demonstration.
+
+## Modals and dropdowns on mobile
+
+### Overflow and scrolling
+
+Support for `overflow: hidden;` on the `<body>` element is quite limited in iOS and Android. To that end, when you scroll past the top or bottom of a modal in either of those devices' browsers, the `<body>` content will begin to scroll. See [Chrome bug #175502](https://bugs.chromium.org/p/chromium/issues/detail?id=175502) (fixed in Chrome v40) and [WebKit bug #153852](https://bugs.webkit.org/show_bug.cgi?id=153852).
+
+### iOS text fields and scrolling
+
+As of iOS 9.2, while a modal is open, if the initial touch of a scroll gesture is within the boundary of a textual `<input>` or a `<textarea>`, the `<body>` content underneath the modal will be scrolled instead of the modal itself. See [WebKit bug #153856](https://bugs.webkit.org/show_bug.cgi?id=153856).
+
+### Navbar Dropdowns
+
+The `.dropdown-backdrop` element isn't used on iOS in the nav because of the complexity of z-indexing. Thus, to close dropdowns in navbars, you must directly click the dropdown element (or [any other element which will fire a click event in iOS](https://developer.mozilla.org/en-US/docs/Web/Events/click#Safari_Mobile)).
+
+## Browser zooming
+
+Page zooming inevitably presents rendering artifacts in some components, both in Bootstrap and the rest of the web. Depending on the issue, we may be able to fix it (search first and then open an issue if need be). However, we tend to ignore these as they often have no direct solution other than hacky workarounds.
+
+## Sticky `:hover`/`:focus` on mobile
+Even though real hovering isn't possible on most touchscreens, most mobile browsers emulate hovering support and make `:hover` "sticky". In other words, `:hover` styles start applying after tapping an element and only stop applying after the user taps some other element. On mobile-first sites, this behavior is normally undesirable.
+
+Bootstrap includes a workaround for this, although it is disabled by default. By setting `$enable-hover-media-query` to `true` when compiling from Sass, Bootstrap will use [mq4-hover-shim](https://github.com/twbs/mq4-hover-shim) to disable `:hover` styles in browsers that emulate hovering, thus preventing sticky `:hover` styles. There are some caveats to this workaround; see the shim's documentation for details.
+
+## Printing
+
+Even in some modern browsers, printing can be quirky.
+
+As of Safari v8.0, use of the fixed-width `.container` class can cause Safari to use an unusually small font size when printing. See [issue #14868](https://github.com/twbs/bootstrap/issues/14868) and [WebKit bug #138192](https://bugs.webkit.org/show_bug.cgi?id=138192) for more details. One potential workaround is the following CSS:
+
+{% highlight css %}
+@media print {
+  .container {
+    width: auto;
+  }
+}
+{% endhighlight %}
+
+## Android stock browser
+
+Out of the box, Android 4.1 (and even some newer releases apparently) ship with the Browser app as the default web browser of choice (as opposed to Chrome). Unfortunately, the Browser app has lots of bugs and inconsistencies with CSS in general.
+
+#### Select menu
+
+On `<select>` elements, the Android stock browser will not display the side controls if there is a `border-radius` and/or `border` applied. (See [this StackOverflow question](https://stackoverflow.com/questions/14744437/html-select-box-not-showing-drop-down-arrow-on-android-version-4-0-when-set-with) for details.) Use the snippet of code below to remove the offending CSS and render the `<select>` as an unstyled element on the Android stock browser. The user agent sniffing avoids interference with Chrome, Safari, and Mozilla browsers.
+
+{% highlight html %}
+<script>
+$(function () {
+  var nua = navigator.userAgent
+  var isAndroid = (nua.indexOf('Mozilla/5.0') > -1 && nua.indexOf('Android ') > -1 && nua.indexOf('AppleWebKit') > -1 && nua.indexOf('Chrome') === -1)
+  if (isAndroid) {
+    $('select.form-control').removeClass('form-control').css('width', '100%')
+  }
+})
+</script>
+{% endhighlight %}
+
+Want to see an example? [Check out this JS Bin demo.](http://jsbin.com/OyaqoDO/2)
+
+## Validators
+
+In order to provide the best possible experience to old and buggy browsers, Bootstrap uses [CSS browser hacks](http://browserhacks.com) in several places to target special CSS to certain browser versions in order to work around bugs in the browsers themselves. These hacks understandably cause CSS validators to complain that they are invalid. In a couple places, we also use bleeding-edge CSS features that aren't yet fully standardized, but these are used purely for progressive enhancement.
+
+These validation warnings don't matter in practice since the non-hacky portion of our CSS does fully validate and the hacky portions don't interfere with the proper functioning of the non-hacky portion, hence why we deliberately ignore these particular warnings.
+
+Our HTML docs likewise have some trivial and inconsequential HTML validation warnings due to our inclusion of a workaround for [a certain Firefox bug](https://bugzilla.mozilla.org/show_bug.cgi?id=654072).
diff --git a/docs/4.0/getting-started/build-tools.md b/docs/4.0/getting-started/build-tools.md
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+---
+layout: docs
+title: Build tools
+description: Learn how to use Bootstrap's included npm scripts to build our documentation, compile source code, run tests, and more.
+group: getting-started
+toc: true
+---
+
+## Tooling setup
+
+Bootstrap uses [NPM scripts](https://docs.npmjs.com/misc/scripts) for its build system. Our [package.json](https://github.com/twbs/bootstrap/blob/v4-dev/package.json) includes convenient methods for working with the framework, including compiling code, running tests, and more.
+
+To use our build system and run our documentation locally, you'll need a copy of Bootstrap's source files and Node. Follow these steps and you should be ready to rock:
+
+1. [Download and install Node](https://nodejs.org/download/), which we use to manage our dependencies.
+2. Navigate to the root `/bootstrap` directory and run `npm install` to install our local dependencies listed in [package.json](https://github.com/twbs/bootstrap/blob/master/package.json).
+4. [Install Ruby][install-ruby], install [Bundler][gembundler] with `gem install bundler`, and finally run `bundle install`. This will install all Ruby dependencies, such as Jekyll and plugins.
+  - **Windows users:** Read [this unofficial guide](http://jekyll-windows.juthilo.com/) to get Jekyll up and running without problems.
+
+When completed, you'll be able to run the various commands provided from the command line.
+
+[install-ruby]: https://www.ruby-lang.org/en/documentation/installation/
+[gembundler]: https://bundler.io/
+
+## Using NPM scripts
+
+Our [package.json](https://github.com/twbs/bootstrap/blob/master/package.json) includes the following commands and tasks:
+
+| Task | Description |
+| --- | --- |
+| `npm test` | Run `npm test` to run tests locally and compile the CSS and JavaScript into `/dist`. **Uses [Sass](http://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](http://lisperator.net/uglifyjs/).** |
+| `npm run dist` | `npm run dist` creates the `/dist` directory with compiled files. **Uses [Sass](http://sass-lang.com/), [Autoprefixer][autoprefixer], and [UglifyJS](http://lisperator.net/uglifyjs/).** |
+| `npm run docs` | Builds and tests CSS, JavaScript, and other assets which are used when running the documentation locally via `npm run docs-serve`. |
+
+## Autoprefixer
+
+Bootstrap uses [Autoprefixer][autoprefixer] (included in our build process) to automatically add vendor prefixes to some CSS properties at build time. Doing so saves us time and code by allowing us to write key parts of our CSS a single time while eliminating the need for vendor mixins like those found in v3.
+
+We maintain the list of browsers supported through Autoprefixer in a separate file within our GitHub repository. See [`/build/postcss.config.js`](https://github.com/twbs/bootstrap/blob/v4-dev/build/postcss.config.js) for details.
+
+## Local documentation
+
+Running our documentation locally requires the use of Jekyll, a decently flexible static site generator that provides us: basic includes, Markdown-based files, templates, and more. Here's how to get it started:
+
+1. Run through the [tooling setup](#tooling-setup) above to install Jekyll (the site builder) and other Ruby dependencies with `bundle install`.
+2. From the root `/bootstrap` directory, run `npm run docs-serve` in the command line.
+3. Open <http://localhost:9001> in your browser, and voilà.
+
+Learn more about using Jekyll by reading its [documentation](https://jekyllrb.com/docs/home/).
+
+## Troubleshooting
+
+Should you encounter problems with installing dependencies, uninstall all previous dependency versions (global and local). Then, rerun `npm install`.
+
+[autoprefixer]: https://github.com/postcss/autoprefixer
diff --git a/docs/4.0/getting-started/contents.md b/docs/4.0/getting-started/contents.md
new file mode 100644
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--- /dev/null
+++ b/docs/4.0/getting-started/contents.md
@@ -0,0 +1,44 @@
+---
+layout: docs
+title: Contents
+description: Discover what's included in Bootstrap, including our precompiled and source code flavors. Remember, Bootstrap's JavaScript plugins require jQuery.
+group: getting-started
+toc: true
+---
+
+## Precompiled Bootstrap
+
+Once downloaded, unzip the compressed folder and you'll see something like this:
+
+<!-- NOTE: This info is intentionally duplicated in the README. Copy any changes made here over to the README too. -->
+
+{% highlight plaintext %}
+bootstrap/
+├── css/
+│   ├── bootstrap.css
+│   ├── bootstrap.css.map
+│   ├── bootstrap.min.css
+│   └── bootstrap.min.css.map
+└── js/
+    ├── bootstrap.js
+    └── bootstrap.min.js
+{% endhighlight %}
+
+This is the most basic form of Bootstrap: precompiled files for quick drop-in usage in nearly any web project. We provide compiled CSS and JS (`bootstrap.*`), as well as compiled and minified CSS and JS (`bootstrap.min.*`). CSS [source maps](https://developers.google.com/web/tools/chrome-devtools/javascript/source-maps) (`bootstrap.*.map`) are available for use with certain browsers' developer tools.
+
+## Bootstrap source code
+
+The Bootstrap source code download includes the precompiled CSS and JavaScript assets, along with source Sass, JavaScript, and documentation. More specifically, it includes the following and more:
+
+{% highlight plaintext %}
+bootstrap/
+├── dist/
+│   ├── css/
+│   └── js/
+├── docs/
+│   └── examples/
+├── js/
+└── scss/
+{% endhighlight %}
+
+The `scss/` and `js/` are the source code for our CSS and JavaScript. The `dist/` folder includes everything listed in the precompiled download section above. The `docs/` folder includes the source code for our documentation, and `examples/` of Bootstrap usage. Beyond that, any other included file provides support for packages, license information, and development.
diff --git a/docs/4.0/getting-started/download.md b/docs/4.0/getting-started/download.md
new file mode 100644
index 000000000..dc85ef50a
--- /dev/null
+++ b/docs/4.0/getting-started/download.md
@@ -0,0 +1,94 @@
+---
+layout: docs
+title: Download
+description: Download Bootstrap to get the compiled CSS and JavaScript, source code, or include it with your favorite package managers like npm, Bower, RubyGems, and more.
+group: getting-started
+toc: true
+---
+
+## Bootstrap CSS and JS
+
+**Download Bootstrap's ready-to-use code to easily drop into your project.** Includes compiled and minified versions of all our CSS bundles (default, grid only, or Reboot only) and JavaScript plugins. Doesn't include documentation or source files.
+
+**Current version:** v{{ site.current_version}}
+
+<a href="{{ site.download.dist }}" class="btn btn-lg btn-bs" onclick="ga('send', 'event', 'Getting started', 'Download', 'Download Bootstrap');">Download Bootstrap</a>
+
+## Source files
+**Want to compile Bootstrap with your project's asset pipeline?** Choose this option to download our source Sass, JavaScript, and documentation files. Requires a Sass compiler, [Autoprefixer](https://github.com/postcss/autoprefixer), [postcss-flexbugs-fixes](https://github.com/luisrudge/postcss-flexbugs-fixes), and [some setup]({{ site.baseurl }}/getting-started/build-tools/#tooling-setup).
+
+<a href="{{ site.download.source }}" class="btn btn-bs" onclick="ga('send', 'event', 'Getting started', 'Download', 'Download source');">Download source</a>
+
+## Bootstrap CDN
+
+Skip the download and use the Bootstrap CDN to deliver Bootstrap's compiled CSS and JS to your project.
+
+{% highlight html %}
+<link rel="stylesheet" href="{{ site.cdn.css }}" integrity="{{ site.cdn.css_hash }}" crossorigin="anonymous">
+<script src="{{ site.cdn.js }}" integrity="{{ site.cdn.js_hash }}" crossorigin="anonymous"></script>
+{% endhighlight %}
+
+## Package managers
+
+Pull in Bootstrap's **source files** into nearly any project with some of the most popular package managers. No matter the package manager, Bootstrap will **require a Sass compiler, [Autoprefixer](https://github.com/postcss/autoprefixer), and [postcss-flexbugs-fixes](https://github.com/luisrudge/postcss-flexbugs-fixes)** for a setup that matches our official compiled versions.
+
+### npm
+
+Install Bootstrap in your Node powered apps with [the npm package](https://www.npmjs.com/package/bootstrap):
+
+{% highlight bash %}
+npm install bootstrap@{{ site.current_version }}
+{% endhighlight %}
+
+`require('bootstrap')` will load all of Bootstrap's jQuery plugins onto the jQuery object. The `bootstrap` module itself does not export anything. You can manually load Bootstrap's jQuery plugins individually by loading the `/js/*.js` files under the package's top-level directory.
+
+Bootstrap's `package.json` contains some additional metadata under the following keys:
+
+- `sass` - path to Bootstrap's main [Sass](http://sass-lang.com/) source file
+- `style` - path to Bootstrap's non-minified CSS that's been precompiled using the default settings (no customization)
+
+### RubyGems
+
+Install Bootstrap in your Ruby apps using [Bundler](https://bundler.io/) (**recommended**) and [RubyGems](https://rubygems.org/) by adding the following line to your [`Gemfile`](https://bundler.io/gemfile.html):
+
+{% highlight ruby %}
+gem 'bootstrap', '~> 4.0.0.alpha6'
+{% endhighlight %}
+
+Alternatively, if you're not using Bundler, you can install the gem by running this command:
+
+{% highlight bash %}
+gem install bootstrap -v 4.0.0.alpha6
+{% endhighlight %}
+
+[See the gem's README](https://github.com/twbs/bootstrap-rubygem/blob/master/README.md) for further details.
+
+### Composer
+
+You can also install and manage Bootstrap's Sass and JavaScript using [Composer](https://getcomposer.org):
+
+{% highlight bash %}
+composer require twbs/bootstrap:{{ site.current_version }}
+{% endhighlight %}
+
+### Bower
+
+Install and manage Bootstrap's Sass and JavaScript using [Bower](https://bower.io).
+
+{% highlight bash %}
+bower install bootstrap#v{{ site.current_version }}
+{% endhighlight %}
+
+### NuGet
+
+If you develop in .NET, you can also install and manage Bootstrap's [CSS](https://www.nuget.org/packages/bootstrap/) or [Sass](https://www.nuget.org/packages/bootstrap.sass/) and JavaScript using [NuGet](https://www.nuget.org):
+
+{% highlight powershell %}
+Install-Package bootstrap -Pre
+{% endhighlight %}
+
+{% highlight powershell %}
+Install-Package bootstrap.sass -Pre
+{% endhighlight %}
+
+The `-Pre` is required until Bootstrap v4 has a stable release.
diff --git a/docs/4.0/getting-started/introduction.md b/docs/4.0/getting-started/introduction.md
new file mode 100644
index 000000000..a9714eb6d
--- /dev/null
+++ b/docs/4.0/getting-started/introduction.md
@@ -0,0 +1,121 @@
+---
+layout: docs
+title: Introduction
+description: Get started with Bootstrap, the world's most popular framework for building responsive, mobile-first sites, with the Bootstrap CDN and a template starter page.
+group: getting-started
+redirect_from:
+  - /getting-started/
+  - /docs/4.0/
+  - /docs/
+toc: true
+---
+
+<!-- Bootstrap is the world's most popular framework for building responsive, mobile-first sites and applications. Inside you'll find high quality HTML, CSS, and JavaScript to make starting any project easier than ever. -->
+
+<!-- Here's how to quickly get started with the Bootstrap CDN and a template starter page. -->
+
+## Quick start
+
+Looking to quickly add Bootstrap to your project? Use the Bootstrap CDN, provided for free by the folks at MaxCDN. Using a package manager or need to download the source files? [Head to the downloads page.]({{ site.baseurl }}/getting-started/download/)
+
+Copy-paste the stylesheet `<link>` into your `<head>` before all other stylesheets to load our CSS.
+
+{% highlight html %}
+<link rel="stylesheet" href="{{ site.cdn.css }}" integrity="{{ site.cdn.css_hash }}" crossorigin="anonymous">
+{% endhighlight %}
+
+Add our JavaScript plugins, jQuery, and Popper.js near the end of your pages, right before the closing `</body>` tag. Be sure to place jQuery and Popper.js first, as our code depends on them. While we use [jQuery's slim build](https://blog.jquery.com/2016/06/09/jquery-3-0-final-released/) in our docs, the full version is also supported.
+
+{% highlight html %}
+<script src="{{ site.cdn.jquery }}" integrity="{{ site.cdn.jquery_hash }}" crossorigin="anonymous"></script>
+<script src="{{ site.cdn.popper }}" integrity="{{ site.cdn.popper_hash }}" crossorigin="anonymous"></script>
+<script src="{{ site.cdn.js }}" integrity="{{ site.cdn.js_hash }}" crossorigin="anonymous"></script>
+{% endhighlight %}
+
+And that's it—you're on your way to a fully Bootstrapped site. If you're at all unsure about the general page structure, keep reading for an example page template.
+
+## Starter template
+
+Be sure to have your pages set up with the latest design and development standards. That means using an HTML5 doctype and including a viewport meta tag for proper responsive behaviors. Put it all together and your pages should look like this:
+
+{% highlight html %}
+<!DOCTYPE html>
+<html lang="en">
+  <head>
+    <!-- Required meta tags -->
+    <meta charset="utf-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+
+    <!-- Bootstrap CSS -->
+    <link rel="stylesheet" href="{{ site.cdn.css }}" integrity="{{ site.cdn.css_hash }}" crossorigin="anonymous">
+  </head>
+  <body>
+    <h1>Hello, world!</h1>
+
+    <!-- jQuery first, then Popper.js, then Bootstrap JS. -->
+    <script src="{{ site.cdn.jquery }}" integrity="{{ site.cdn.jquery_hash }}" crossorigin="anonymous"></script>
+    <script src="{{ site.cdn.popper }}" integrity="{{ site.cdn.popper_hash }}" crossorigin="anonymous"></script>
+    <script src="{{ site.cdn.js }}" integrity="{{ site.cdn.js_hash }}" crossorigin="anonymous"></script>
+  </body>
+</html>
+{% endhighlight %}
+
+That's all you need for overall page requirements. Visit the [Layout docs]({{ site.baseurl }}/layout/overview/) or [our official examples]({{ site.baseurl }}/examples/) to start laying out your site's content and components.
+
+## Important globals
+
+Bootstrap employs a handful of important global styles and settings that you'll need to be aware of when using it, all of which are almost exclusively geared towards the *normalization* of cross browser styles. Let's dive in.
+
+### HTML5 doctype
+
+Bootstrap requires the use of the HTML5 doctype. Without it, you'll see some funky incomplete styling, but including it shouldn't cause any considerable hiccups.
+
+{% highlight html %}
+<!DOCTYPE html>
+<html lang="en">
+  ...
+</html>
+{% endhighlight %}
+
+### Responsive meta tag
+
+Bootstrap is developed *mobile first*, a strategy in which we optimize code for mobile devices first and then scale up components as necessary using CSS media queries. To ensure proper rendering and touch zooming for all devices, **add the responsive viewport meta tag** to your `<head>`.
+
+{% highlight html %}
+<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
+{% endhighlight %}
+
+You can see an example of this in action in the [starter template](#starter-template).
+
+### Box-sizing
+
+For more straightforward sizing in CSS, we switch the global `box-sizing` value from `content-box` to `border-box`. This ensures `padding` does not affect the final computed width of an element, but it can cause problems with some third party software like Google Maps and Google Custom Search Engine.
+
+On the rare occasion you need to override it, use something like the following:
+
+{% highlight scss %}
+.selector-for-some-widget {
+  box-sizing: content-box;
+}
+{% endhighlight %}
+
+With the above snippet, nested elements—including generated content via `:before` and `:after`—will all inherit the specified `box-sizing` for that `.selector-for-some-widget`.
+
+Learn more about [box model and sizing at CSS Tricks](https://css-tricks.com/box-sizing/).
+
+### Reboot
+
+For improved cross-browser rendering, we use [Reboot]({{ site.baseurl }}/content/reboot/) to correct inconsistencies across browsers and devices while providing slightly more opinionated resets to common HTML elements.
+
+## Community
+
+Stay up to date on the development of Bootstrap and reach out to the community with these helpful resources.
+
+- Follow [@getbootstrap on Twitter](https://twitter.com/getbootstrap).
+- Read and subscribe to [The Official Bootstrap Blog]({{ site.blog }}).
+- Join [the official Slack room]({{ site.slack }}).
+- Chat with fellow Bootstrappers in IRC. On the `irc.freenode.net` server, in the `##bootstrap` channel.
+- Implementation help may be found at Stack Overflow (tagged [`bootstrap-4`](https://stackoverflow.com/questions/tagged/bootstrap-4)).
+- Developers should use the keyword `bootstrap` on packages which modify or add to the functionality of Bootstrap when distributing through [npm](https://www.npmjs.com/browse/keyword/bootstrap) or similar delivery mechanisms for maximum discoverability.
+
+You can also follow [@getbootstrap on Twitter](https://twitter.com/getbootstrap) for the latest gossip and awesome music videos.
diff --git a/docs/4.0/getting-started/javascript.md b/docs/4.0/getting-started/javascript.md
new file mode 100644
index 000000000..c4fb2366a
--- /dev/null
+++ b/docs/4.0/getting-started/javascript.md
@@ -0,0 +1,122 @@
+---
+layout: docs
+title: JavaScript
+description: Bring Bootstrap to life with our JavaScript plugins built on jQuery. Learn about each plugin, our data and programmatic API options, and more.
+group: getting-started
+toc: true
+---
+
+## Individual or compiled
+
+Plugins can be included individually (using Bootstrap's individual `*.js` files), or all at once using `bootstrap.js` or the minified `bootstrap.min.js` (don't include both).
+
+## Dependencies
+
+Some plugins and CSS components depend on other plugins. If you include plugins individually, make sure to check for these dependencies in the docs. Also note that all plugins depend on jQuery (this means jQuery must be included **before** the plugin files). [Consult our `bower.json`]({{ site.repo }}/blob/v{{ site.current_version }}/bower.json) to see which versions of jQuery are supported.
+
+## Data attributes
+
+Nearly all Bootstrap plugins can be enabled and configured through HTML alone with data attributes (our preferred way of using JavaScript functionality). Be sure to **only use one set of data attributes on a single element** (e.g., you cannot trigger a tooltip and modal from the same button.)
+
+However, in some situations it may be desirable to disable this functionality. To disable the data attribute API, unbind all events on the document namespaced with `data-api` like so:
+
+{% highlight js %}
+$(document).off('.data-api')
+{% endhighlight %}
+
+Alternatively, to target a specific plugin, just include the plugin's name as a namespace along with the data-api namespace like this:
+
+{% highlight js %}
+$(document).off('.alert.data-api')
+{% endhighlight %}
+
+## Events
+
+Bootstrap provides custom events for most plugins' unique actions. Generally, these come in an infinitive and past participle form - where the infinitive (ex. `show`) is triggered at the start of an event, and its past participle form (ex. `shown`) is triggered on the completion of an action.
+
+All infinitive events provide [`preventDefault()`](https://developer.mozilla.org/en-US/docs/Web/API/Event/preventDefault) functionality. This provides the ability to stop the execution of an action before it starts.
+
+{% highlight js %}
+$('#myModal').on('show.bs.modal', function (e) {
+  if (!data) return e.preventDefault() // stops modal from being shown
+})
+{% endhighlight %}
+
+## Programmatic API
+
+We also believe you should be able to use all Bootstrap plugins purely through the JavaScript API. All public APIs are single, chainable methods, and return the collection acted upon.
+
+{% highlight js %}
+$('.btn.danger').button('toggle').addClass('fat')
+{% endhighlight %}
+
+All methods should accept an optional options object, a string which targets a particular method, or nothing (which initiates a plugin with default behavior):
+
+{% highlight js %}
+$('#myModal').modal()                      // initialized with defaults
+$('#myModal').modal({ keyboard: false })   // initialized with no keyboard
+$('#myModal').modal('show')                // initializes and invokes show immediately
+{% endhighlight %}
+
+Each plugin also exposes its raw constructor on a `Constructor` property: `$.fn.popover.Constructor`. If you'd like to get a particular plugin instance, retrieve it directly from an element: `$('[rel="popover"]').data('popover')`.
+
+### Asynchronous functions and transitions
+
+All programmatic API methods are **asynchronous** and returns to the caller once the transition is started but **before it ends**.
+
+In order to execute an action once the transition is complete, you can listen to the corresponding event.
+{% highlight js %}
+$('#myCollapse').on('shown.bs.collapse', function (e) {
+  // Action to execute once the collapsible area is expanded
+})
+{% endhighlight %}
+
+In addition a method call on a **transitioning component will be ignored**.
+{% highlight js %}
+$('#myCarousel').on('slid.bs.carousel', function (e) {
+  $('#myCarousel').carousel('2') // Will slide to the slide 2 as soon as the transition to slide 1 is finished
+})
+
+$('#myCarousel').carousel('1') // Will start sliding to the slide 1 and returns to the caller
+$('#myCarousel').carousel('2') // !! Will be ignored, as the transition to the slide 1 is not finished !!
+{% endhighlight %}
+
+### Default settings
+You can change the default settings for a plugin by modifying the plugin's `Constructor.Default` object:
+
+{% highlight js %}
+$.fn.modal.Constructor.Default.keyboard = false // changes default for the modal plugin's `keyboard` option to false
+{% endhighlight %}
+
+## No conflict
+
+Sometimes it is necessary to use Bootstrap plugins with other UI frameworks. In these circumstances, namespace collisions can occasionally occur. If this happens, you may call `.noConflict` on the plugin you wish to revert the value of.
+
+{% highlight js %}
+var bootstrapButton = $.fn.button.noConflict() // return $.fn.button to previously assigned value
+$.fn.bootstrapBtn = bootstrapButton            // give $().bootstrapBtn the Bootstrap functionality
+{% endhighlight %}
+
+## Version numbers
+
+The version of each of Bootstrap's jQuery plugins can be accessed via the `VERSION` property of the plugin's constructor. For example, for the tooltip plugin:
+
+{% highlight js %}
+$.fn.tooltip.Constructor.VERSION // => "{{ site.current_version }}"
+{% endhighlight %}
+
+## No special fallbacks when JavaScript is disabled
+
+Bootstrap's plugins don't fall back particularly gracefully when JavaScript is disabled. If you care about the user experience in this case, use [`<noscript>`](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/noscript) to explain the situation (and how to re-enable JavaScript) to your users, and/or add your own custom fallbacks.
+
+{% callout warning %}
+#### Third-party libraries
+
+**Bootstrap does not officially support third-party JavaScript libraries** like Prototype or jQuery UI. Despite `.noConflict` and namespaced events, there may be compatibility problems that you need to fix on your own.
+{% endcallout %}
+
+## Util
+
+All Bootstrap Javascript depend on `util.js` and it has to be included alongside the other JS files. If you're using the compiled (or minified) `bootstrap.js`, there is no need to include this—it's already there.
+
+`util.js` includes utility functions and a basic helper for `transitionEnd` events as well as a CSS transition emulator. It's used by the other plugins to check for CSS transition support and to catch hanging transitions.
diff --git a/docs/4.0/getting-started/options.md b/docs/4.0/getting-started/options.md
new file mode 100644
index 000000000..acc7ce451
--- /dev/null
+++ b/docs/4.0/getting-started/options.md
@@ -0,0 +1,42 @@
+---
+layout: docs
+title: Customization options
+description: Customize Bootstrap 4 with our built-in custom variables file and easily toggle global CSS preferences with new Sass variables.
+group: getting-started
+toc: true
+---
+
+## Customizing variables
+
+Bootstrap 4 ships with a `_custom.scss` file for easy overriding of default variables in `/scss/_variables.scss`. Copy and paste relevant lines from there into the `_custom.scss` file, modify the values, and recompile your Sass to change our default values. **Be sure to remove the `!default` flag from override values.**
+
+For example, to change out the `background-color` and `color` for the `<body>`, you'd do the following:
+
+{% highlight scss %}
+// Bootstrap overrides
+//
+// Copy variables from `_variables.scss` to this file to override default values
+// without modifying source files.
+
+$body-bg:    $gray-dark;
+$body-color: $gray-light;
+{% endhighlight %}
+
+Do the same for any variable you need to override, including the global options listed below.
+
+## Global options
+
+Customize Bootstrap 4 with our built-in custom variables file and easily toggle global CSS preferences with new `$enable-*` Sass variables. Override a variable's value and recompile with `npm run test` as needed.
+
+You can find and customize these variables for key global options in our `_variables.scss` file.
+
+| Variable                    | Values                             | Description                                                                            |
+| --------------------------- | ---------------------------------- | -------------------------------------------------------------------------------------- |
+| `$spacer`                   | `1rem` (default), or any value > 0 | Specifies the default spacer value to programmatically generate our [spacer utilities](/utilities/spacing/). |
+| `$enable-rounded`           | `true` (default) or `false`        | Enables predefined `border-radius` styles on various components.                       |
+| `$enable-shadows`           | `true` or `false` (default)        | Enables predefined `box-shadow` styles on various components.                          |
+| `$enable-gradients`         | `true` or `false` (default)        | Enables predefined gradients via `background-image` styles on various components.      |
+| `$enable-transitions`       | `true` (default) or `false`        | Enables predefined `transition`s on various components.                                |
+| `$enable-hover-media-query` | `true` or `false` (default)        | ...                                                                                    |
+| `$enable-grid-classes`      | `true` (default) or `false`        | Enables the generation of CSS classes for the grid system (e.g., `.container`, `.row`, `.col-md-1`, etc.).     |
+| `$enable-print-styles`      | `true` (default) or `false`        | Enables styles for optimizing printing.                                |
diff --git a/docs/4.0/getting-started/webpack.md b/docs/4.0/getting-started/webpack.md
new file mode 100644
index 000000000..dd246e045
--- /dev/null
+++ b/docs/4.0/getting-started/webpack.md
@@ -0,0 +1,99 @@
+---
+layout: docs
+title: Webpack
+description: Learn how to include Bootstrap in your project using Webpack 2.
+group: getting-started
+toc: true
+---
+
+## Installing Bootstrap
+
+[Install bootstrap](/getting-started/download/#npm) as a node module using npm.
+
+## Importing JavaScript
+
+Import [Bootstrap's JavaScript](/getting-started/javascript/) by adding this line to your app's entry point (usally `index.js` or `app.js`):
+
+{% highlight js %}
+import 'bootstrap';
+{% endhighlight %}
+
+Alternatively, you may **import plugins individually** as needed:
+
+{% highlight js %}
+import 'bootstrap/js/dist/util';
+import 'bootstrap/js/dist/dropdown';
+...
+{% endhighlight %}
+
+Bootstrap is dependent on [jQuery](https://jquery.com/) and [Popper](https://popper.js.org/), so npm will install them for you if needed. But they must be explicitly provided by webpack. Add the following code to the `plugins` section in your webpack config file:
+
+{% highlight js %}
+  plugins: [
+    ...
+      new webpack.ProvidePlugin({
+        $: 'jquery',
+        jQuery: 'jquery',
+        'window.jQuery': 'jquery',
+        Popper: ['popper.js', 'default'],
+        // In case you imported plugins individually, you must also require them here:
+        Util: "exports-loader?Util!bootstrap/js/dist/util",
+        Dropdown: "exports-loader?Dropdown!bootstrap/js/dist/dropdown",
+        ...
+      })
+    ...
+  ]
+{% endhighlight %}
+
+{% callout warning %}
+Notice that if you chose to **import plugins individually**, you must also install [exports-loader](https://github.com/webpack-contrib/exports-loader)
+{% endcallout %}
+
+## Importing Styles
+
+### Importing Precompiled SASS
+
+To enjoy the full potential of Bootstrap and customize it to your needs, use the source files as a part of your project's bundling process.
+
+First, create your own `_custom.scss` and use it to override the [built-in custom variables](/getting-started/options/). Then, use your main sass file to import your custom variables, followed by Bootstrap:
+{% highlight scss %}
+@import "custom";
+@import "~bootstrap/scss/bootstrap";
+{% endhighlight %}
+
+For Bootstrap to compile, make sure you install and use the required loaders: [sass-loader](https://github.com/webpack-contrib/sass-loader), [postcss-loader](https://github.com/postcss/postcss-loader) with [Autoprefixer](https://github.com/postcss/autoprefixer#webpack) and [postcss-flexbugs-fixes](https://github.com/luisrudge/postcss-flexbugs-fixes). With minimal setup, your webpack config should include this rule or similar:
+
+{% highlight js %}
+  ...
+  {
+    test: /\.(scss)$/,
+    use: [{
+      loader: 'style-loader', // inject CSS to page
+    }, {
+      loader: 'css-loader', // translates CSS into CommonJS modules
+    }, {
+      loader: 'postcss-loader', // Run post css actions
+      options: {
+        plugins: function () { // post css plugins, can be exported to postcss.config.js
+          return [
+            require('precss'),
+            require('autoprefixer')
+          ];
+        }
+      }
+    }, {
+      loader: 'sass-loader' // compiles SASS to CSS
+    }]
+  },
+  ...
+{% endhighlight %}
+
+### Importing Compiled CSS
+
+Alternatively, you may use Bootstrap's ready-to-use css by simply adding this line to your project's entry point:
+
+{% highlight js %}
+import 'bootstrap/dist/css/bootstrap.min.css';
+{% endhighlight %}
+
+In this case you may use your existing rule for `css` without any special modifications to webpack config.