respect the opinions of others.

* Please **do not** post comments consisting solely of "+1" or ":thumbsup:".

instead. We reserve the right to delete comments which violate this rule.

* Please **do not** open issues regarding the official themes offered on <https://themes.getbootstrap.com/>.

| Vendor(s) | Browser(s) | Rendering engine | Bug reporting website(s) | Notes |

| ------------- | ---------------------------- | ---------------- | ------------------------------------------------------------------------------------- | -------------------------------------------------------- |

| Mozilla | Firefox | Gecko | https://bugzilla.mozilla.org/enter_bug.cgi | "Core" is normally the right product option to choose. |

| Microsoft | Edge | EdgeHTML | https://developer.microsoft.com/en-us/microsoft-edge/platform/issues/ | |

"framework",

"web"

],

"authors": [

{

"name": "Mark Otto",

Bootstrap was created at Twitter in mid-2010 by [@mdo](https://twitter.com/mdo) and [@fat](https://twitter.com/fat). Prior to being an open-sourced framework, Bootstrap was known as _Twitter Blueprint_. A few months into development, Twitter held its [first Hack Week](https://blog.twitter.com/2010/hack-week) and the project exploded as developers of all skill levels jumped in without any external guidance. It served as the style guide for internal tools development at the company for over a year before its public release, and continues to do so today.

With Bootstrap 4, we once again rewrote the project to account for two key architectural changes: a migration to Sass and the move to CSS's flexbox. Our intention is to help in a small way to move the web development community forward by pushing for newer CSS properties, fewer dependencies, and new technologies across more modern browsers.

See also:

* [Mozilla bug 1230801: Fix the issues that affect Bootstrap](https://bugzilla.mozilla.org/show_bug.cgi?id=1230801)

* [WebKit bug 159753: [meta] Issues affecting Bootstrap](https://bugs.webkit.org/show_bug.cgi?id=159753)

* [jQuery's browser bug workarounds](https://docs.google.com/document/d/1LPaPA30bLUB_publLIMF0RlhdnPx_ePXm7oW02iiT6o)

Bootstrap's dropdowns, on the other hand, are designed to be generic and applicable to a variety of situations and markup structures. For instance, it is possible to create dropdowns that contain additional inputs and form controls, such as search fields or login forms. For this reason, Bootstrap does not expect (nor automatically add) any of the `role` and `aria-` attributes required for true <abbr title="Accessible Rich Internet Applications">ARIA</abbr> menus. Authors will have to include these more specific attributes themselves.

<div class="modal-content">

<div class="modal-header">

<button type="button" class="close" data-dismiss="modal" aria-label="Close">

<span aria-hidden="true">&times;</span>

</button>

<div class="modal-dialog modal-sm">

<div class="modal-content">

<div class="modal-header">

<button type="button" class="close" data-dismiss="modal" aria-label="Close">

<span aria-hidden="true">&times;</span>

</button>

<div class="pos-f-t">

<div class="collapse" id="navbarToggleExternalContent">

<div class="bg-dark p-4">

<span class="text-muted">Toggleable via the navbar brand.</span>

</div>

</div>

<div class="jumbotron">

<div class="col-sm-8 mx-auto">

<h1>Navbar examples</h1>

<p>At the smallest breakpoint, the collapse plugin is used to hide the links and show a menu button to toggle the collapsed content.</p>

<p>

<a class="btn btn-primary" href="../../components/navbar/" role="button">View navbar docs &raquo;</a>

</tbody>

</table>

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.

Download ready-to-use compiled code for **Bootstrap v{{ site.current_version}}** to easily drop into your project, which includes:

- Compiled and minified JavaScript plugins

This doesn't include documentation, source files, or any optional JavaScript dependencies (jQuery and Popper.js).

**New to or unfamiliar with flexbox?** [Read this CSS Tricks flexbox guide](https://css-tricks.com/snippets/css/a-guide-to-flexbox/#flexbox-background) for background, terminology, guidelines, and code snippets.

- Grid breakpoints are based on minimum width media queries, meaning **they apply to that one breakpoint and all those above it** (e.g., `.col-sm-4` applies to small, medium, large, and extra large devices, but not the first `xs` breakpoint).

- You can use predefined grid classes (like `.col-4`) or [Sass mixins](#sass-mixins) for more semantic markup.

{% include example.html content=example %}

</div>

<div class="bd-example-row">

{% capture example %}

Internet Explorer 10-11 do not render inline elements like links or images (or `::before` and `::after` pseudo-elements) as flex items. The only workaround is to set a non-inline `display` value (e.g., `block`, `inline-block`, or `flex`). We suggest using `.d-flex`, one of our [display utilities]({{ site.baseurl }}/docs/{{ site.docs_version }}/utilities/display/), as an easy fix.

{% endcapture %}

{% include callout.html content=callout type="warning" %}

{% endhighlight %}

<hr class="half-rule">

</div>

<div class="col-12 col-md-4 p-3 p-md-5 bg-light border border-white">

"framework",

"web"

],

"author": "The Bootstrap Authors (https://github.com/twbs/bootstrap/graphs/contributors)",

"contributors": [

"Twitter, Inc."

.card {

display: flex;

flex: 1 0 0%;

flex-direction: column;

margin-right: $card-deck-margin;

// The child selector allows nested `.card` within `.card-group`

// to display properly.

> .card {

flex: 1 0 0%;

margin-bottom: 0;

*::before,

*::after {

// Bootstrap specific; comment out `color` and `background`

text-shadow: none !important;

//background: transparent !important;

box-shadow: none !important;