rooty/Bootstrap
0
0
Fork 0
mirror of https://github.com/twbs/bootstrap.git synced 2025-01-24 16:52:19 +01:00
Code Issues Actions Packages Releases Activity
Bootstrap/docs/4.6/layout/overview/index.html

474 lines
37 KiB
HTML
Raw Normal View History

Add v4.6.0 docs
2021-01-19 08:34:18 +02:00
<!doctype html>
<html lang="en">
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<meta name="description" content="Components and options for laying out your Bootstrap project, including wrapping containers, a powerful grid system, a flexible media object, and responsive utility classes.">
<meta name="author" content="Mark Otto, Jacob Thornton, and Bootstrap contributors">
<meta name="generator" content="Hugo 0.80.0">
<meta name="docsearch:language" content="en">
<meta name="docsearch:version" content="4.6">
<title>Overview · Bootstrap v4.6</title>
<link rel="canonical" href="https://getbootstrap.com/docs/4.6/layout/overview/">
<!-- Bootstrap core CSS -->
<link href="/docs/4.6/dist/css/bootstrap.min.css" rel="stylesheet" integrity="sha384-B0vP5xmATw1+K9KRQjQERJvTumQW0nPEzvF6L/Z6nronJ3oUOFUFpCjEUQouq2+l" crossorigin="anonymous">
<!-- Documentation extras -->
<link href="https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.css" rel="stylesheet">
<link href="/docs/4.6/assets/css/docs.css" rel="stylesheet">
<!-- Favicons -->
<link rel="apple-touch-icon" href="/docs/4.6/assets/img/favicons/apple-touch-icon.png" sizes="180x180">
<link rel="icon" href="/docs/4.6/assets/img/favicons/favicon-32x32.png" sizes="32x32" type="image/png">
<link rel="icon" href="/docs/4.6/assets/img/favicons/favicon-16x16.png" sizes="16x16" type="image/png">
<link rel="manifest" href="/docs/4.6/assets/img/favicons/manifest.json">
<link rel="mask-icon" href="/docs/4.6/assets/img/favicons/safari-pinned-tab.svg" color="#563d7c">
<link rel="icon" href="/docs/4.6/assets/img/favicons/favicon.ico">
<meta name="msapplication-config" content="/docs/4.6/assets/img/favicons/browserconfig.xml">
<meta name="theme-color" content="#563d7c">
<!-- Twitter -->
<meta name="twitter:card" content="summary">
<meta name="twitter:site" content="@getbootstrap">
<meta name="twitter:creator" content="@getbootstrap">
<meta name="twitter:title" content="Overview">
<meta name="twitter:description" content="Components and options for laying out your Bootstrap project, including wrapping containers, a powerful grid system, a flexible media object, and responsive utility classes.">
<meta name="twitter:image" content="https://getbootstrap.com/docs/4.6/assets/brand/bootstrap-social-logo.png">
<!-- Facebook -->
<meta property="og:url" content="https://getbootstrap.com/docs/4.6/layout/overview/">
<meta property="og:title" content="Overview">
<meta property="og:description" content="Components and options for laying out your Bootstrap project, including wrapping containers, a powerful grid system, a flexible media object, and responsive utility classes.">
<meta property="og:type" content="article">
<meta property="og:image" content="https://getbootstrap.com/docs/4.6/assets/brand/bootstrap-social.png">
<meta property="og:image:type" content="image/png">
<meta property="og:image:width" content="1200">
<meta property="og:image:height" content="630">
<script>
window.ga=window.ga||function(){(ga.q=ga.q||[]).push(arguments)};ga.l=+new Date;
ga('create', 'UA-146052-10', 'getbootstrap.com');
ga('set', 'anonymizeIp', true);
ga('send', 'pageview');
</script>
<script async src="https://www.google-analytics.com/analytics.js"></script>
</head>
<body>
<div class="skippy overflow-hidden">
<div class="container-xl">
<a class="sr-only sr-only-focusable d-inline-flex p-2 m-1" href="#content">Skip to main content</a>
<a class="sr-only sr-only-focusable d-none d-md-inline-flex p-2 m-1" href="#bd-docs-nav">Skip to docs navigation</a>
</div>
</div>
<header class="navbar navbar-expand navbar-dark flex-column flex-md-row bd-navbar">
<a class="navbar-brand mr-0 mr-md-2" href="/" aria-label="Bootstrap">
<svg xmlns="http://www.w3.org/2000/svg" width="36" height="36" class="d-block" viewBox="0 0 612 612" role="img" focusable="false"><title>Bootstrap</title><path fill="currentColor" d="M510 8a94.3 94.3 0 0 1 94 94v408a94.3 94.3 0 0 1-94 94H102a94.3 94.3 0 0 1-94-94V102a94.3 94.3 0 0 1 94-94h408m0-8H102C45.9 0 0 45.9 0 102v408c0 56.1 45.9 102 102 102h408c56.1 0 102-45.9 102-102V102C612 45.9 566.1 0 510 0z"/><path fill="currentColor" d="M196.77 471.5V154.43h124.15c54.27 0 91 31.64 91 79.1 0 33-24.17 63.72-54.71 69.21v1.76c43.07 5.49 70.75 35.82 70.75 78 0 55.81-40 89-107.45 89zm39.55-180.4h63.28c46.8 0 72.29-18.68 72.29-53 0-31.42-21.53-48.78-60-48.78h-75.57zm78.22 145.46c47.68 0 72.73-19.34 72.73-56s-25.93-55.37-76.46-55.37h-74.49v111.4z"/></svg>
</a>
<div class="navbar-nav-scroll">
<ul class="navbar-nav bd-navbar-nav flex-row">
<li class="nav-item">
<a class="nav-link" href="/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Bootstrap');">Home</a>
</li>
<li class="nav-item">
<a class="nav-link active" href="/docs/4.6/getting-started/introduction/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Docs');">Documentation</a>
</li>
<li class="nav-item">
<a class="nav-link" href="/docs/4.6/examples/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Examples');">Examples</a>
</li>
<li class="nav-item">
<a class="nav-link" href="https://icons.getbootstrap.com/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Icons');" target="_blank" rel="noopener">Icons</a>
</li>
<li class="nav-item">
<a class="nav-link" href="https://themes.getbootstrap.com/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Themes');" target="_blank" rel="noopener">Themes</a>
</li>
<li class="nav-item">
<a class="nav-link" href="https://expo.getbootstrap.com/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Expo');" target="_blank" rel="noopener">Expo</a>
</li>
<li class="nav-item">
<a class="nav-link" href="https://blog.getbootstrap.com/" onclick="ga('send', 'event', 'Navbar', 'Community links', 'Blog');" target="_blank" rel="noopener">Blog</a>
</li>
</ul>
</div>
<ul class="navbar-nav ml-md-auto">
<li class="nav-item dropdown">
<a class="nav-item nav-link dropdown-toggle mr-md-2" href="#" id="bd-versions" data-toggle="dropdown" aria-haspopup="true" aria-expanded="false">
v4.6
</a>
<div class="dropdown-menu dropdown-menu-md-right" aria-labelledby="bd-versions">
<a class="dropdown-item active" href="/docs/4.6/">Latest (4.6.x)</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="https://getbootstrap.com/docs/5.0/">5.0.x</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="https://getbootstrap.com/docs/3.4/">v3.4.1</a>
<a class="dropdown-item" href="https://getbootstrap.com/2.3.2/">v2.3.2</a>
<div class="dropdown-divider"></div>
<a class="dropdown-item" href="/docs/versions/">All versions</a>
</div>
</li>
<li class="nav-item">
<a class="nav-link pl-2 pr-1 mx-1 py-3 my-n2" href="https://github.com/twbs" target="_blank" rel="noopener" aria-label="GitHub">
<svg xmlns="http://www.w3.org/2000/svg" class="navbar-nav-svg" viewBox="0 0 512 499.36" role="img" focusable="false"><title>GitHub</title><path fill="currentColor" fill-rule="evenodd" d="M256 0C114.64 0 0 114.61 0 256c0 113.09 73.34 209 175.08 242.9 12.8 2.35 17.47-5.56 17.47-12.34 0-6.08-.22-22.18-.35-43.54-71.2 15.49-86.2-34.34-86.2-34.34-11.64-29.57-28.42-37.45-28.42-37.45-23.27-15.84 1.73-15.55 1.73-15.55 25.69 1.81 39.21 26.38 39.21 26.38 22.84 39.12 59.92 27.82 74.5 21.27 2.33-16.54 8.94-27.82 16.25-34.22-56.84-6.43-116.6-28.43-116.6-126.49 0-27.95 10-50.8 26.35-68.69-2.63-6.48-11.42-32.5 2.51-67.75 0 0 21.49-6.88 70.4 26.24a242.65 242.65 0 0 1 128.18 0c48.87-33.13 70.33-26.24 70.33-26.24 14 35.25 5.18 61.27 2.55 67.75 16.41 17.9 26.31 40.75 26.31 68.69 0 98.35-59.85 120-116.88 126.32 9.19 7.9 17.38 23.53 17.38 47.41 0 34.22-.31 61.83-.31 70.23 0 6.85 4.61 14.81 17.6 12.31C438.72 464.97 512 369.08 512 256.02 512 114.62 397.37 0 256 0z"/></svg>
</a>
</li>
<li class="nav-item">
<a class="nav-link px-1 mx-1 py-3 my-n2" href="https://twitter.com/getbootstrap" target="_blank" rel="noopener" aria-label="Twitter">
<svg xmlns="http://www.w3.org/2000/svg" class="navbar-nav-svg" viewBox="0 0 512 416.32" role="img" focusable="false"><title>Twitter</title><path fill="currentColor" d="M160.83 416.32c193.2 0 298.92-160.22 298.92-298.92 0-4.51 0-9-.2-13.52A214 214 0 0 0 512 49.38a212.93 212.93 0 0 1-60.44 16.6 105.7 105.7 0 0 0 46.3-58.19 209 209 0 0 1-66.79 25.37 105.09 105.09 0 0 0-181.73 71.91 116.12 116.12 0 0 0 2.66 24c-87.28-4.3-164.73-46.3-216.56-109.82A105.48 105.48 0 0 0 68 159.6a106.27 106.27 0 0 1-47.53-13.11v1.43a105.28 105.28 0 0 0 84.21 103.06 105.67 105.67 0 0 1-47.33 1.84 105.06 105.06 0 0 0 98.14 72.94A210.72 210.72 0 0 1 25 370.84a202.17 202.17 0 0 1-25-1.43 298.85 298.85 0 0 0 160.83 46.92"/></svg>
</a>
</li>
<li class="nav-item">
<a class="nav-link px-1 mx-1 py-3 my-n2" href="https://bootstrap-slack.herokuapp.com/" target="_blank" rel="noopener" aria-label="Slack">
<svg xmlns="http://www.w3.org/2000/svg" class="navbar-nav-svg" viewBox="0 0 512 512" role="img" focusable="false"><title>Slack</title><path fill="currentColor" d="M210.787 234.832l68.31-22.883 22.1 65.977-68.309 22.882z"/><path fill="currentColor" d="M490.54 185.6C437.7 9.59 361.6-31.34 185.6 21.46S-31.3 150.4 21.46 326.4 150.4 543.3 326.4 490.54 543.34 361.6 490.54 185.6zM401.7 299.8l-33.15 11.05 11.46 34.38c4.5 13.92-2.87 29.06-16.78 33.56-2.87.82-6.14 1.64-9 1.23a27.32 27.32 0 0 1-24.56-18l-11.46-34.38-68.36 22.92 11.46 34.38c4.5 13.92-2.87 29.06-16.78 33.56-2.87.82-6.14 1.64-9 1.23a27.32 27.32 0 0 1-24.56-18l-11.46-34.43-33.15 11.05c-2.87.82-6.14 1.64-9 1.23a27.32 27.32 0 0 1-24.56-18c-4.5-13.92 2.87-29.06 16.78-33.56l33.12-11.03-22.1-65.9-33.15 11.05c-2.87.82-6.14 1.64-9 1.23a27.32 27.32 0 0 1-24.56-18c-4.48-13.93 2.89-29.07 16.81-33.58l33.15-11.05-11.46-34.38c-4.5-13.92 2.87-29.06 16.78-33.56s29.06 2.87 33.56 16.78l11.46 34.38 68.36-22.92-11.46-34.38c-4.5-13.92 2.87-29.06 16.78-33.56s29.06 2.87 33.56 16.78l11.47 34.42 33.15-11.05c13.92-4.5 29.06 2.87 33.56 16.78s-2.87 29.06-16.78 33.56L329.7 194.6l22.1 65.9 33.15-11.05c13.92-4.5 29.06 2.87 33.56 16.78s-2.88 29.07-16.81 33.57z"/></svg>
</a>
</li>
<li class="nav-item">
<a class="nav-link px-1 mx-1 py-3 my-n2" href="https://opencollective.com/bootstrap/" target="_blank" rel="noopener" aria-label="Open Collective">
<svg xmlns="http://www.w3.org/2000/svg" fill="currentColor" fill-rule="evenodd" class="navbar-nav-svg" viewBox="0 0 40 41" role="img" focusable="false"><title>Open Collective</title><path fill-opacity=".4" d="M32.8 21c0 2.4-.8 4.9-2 6.9l5.1 5.1c2.5-3.4 4.1-7.6 4.1-12 0-4.6-1.6-8.8-4-12.2L30.7 14c1.2 2 2 4.3 2 7z"/><path d="M20 33.7a12.8 12.8 0 0 1 0-25.6c2.6 0 5 .7 7 2.1L32 5a20 20 0 1 0 .1 31.9l-5-5.2a13 13 0 0 1-7 2z"/></svg>
</a>
</li>
</ul>
<a class="btn btn-bd-download d-none d-lg-inline-block mb-3 mb-md-0 ml-md-3" href="/docs/4.6/getting-started/download/">Download</a>
</header>
<div class="container-fluid">
<div class="row flex-xl-nowrap">
<div class="col-md-3 col-xl-2 bd-sidebar">
<form role="search" class="bd-search d-flex align-items-center">
<input type="search" class="form-control" id="search-input" placeholder="Search..." aria-label="Search for..." autocomplete="off" data-docs-version="4.6">
<button class="btn bd-search-docs-toggle d-md-none p-0 ml-3" type="button" data-toggle="collapse" data-target="#bd-docs-nav" aria-controls="bd-docs-nav" aria-expanded="false" aria-label="Toggle docs navigation">
<svg xmlns="http://www.w3.org/2000/svg" width="30" height="30" viewBox="0 0 30 30" role="img" focusable="false"><title>Menu</title><path stroke="currentColor" stroke-linecap="round" stroke-miterlimit="10" stroke-width="2" d="M4 7h22M4 15h22M4 23h22"/></svg>
</button>
</form>
<div class="collapse d-md-block row" id="bd-docs-nav">
<nav class="bd-links" aria-label="Main navigation">
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/getting-started/introduction/">
Getting started
</a>
</div>
<div class="bd-toc-item active">
<a class="bd-toc-link" href="/docs/4.6/layout/overview/">
Layout
</a>
<ul class="nav bd-sidenav">
<li class="active bd-sidenav-active">
<a href="/docs/4.6/layout/overview/">Overview</a>
</li>
<li>
<a href="/docs/4.6/layout/grid/">Grid</a>
</li>
<li>
<a href="/docs/4.6/layout/utilities-for-layout/">Utilities for layout</a>
</li>
</ul>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/content/reboot/">
Content
</a>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/components/alerts/">
Components
</a>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/utilities/borders/">
Utilities
</a>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/extend/approach/">
Extend
</a>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/migration/">
Migration
</a>
</div>
<div class="bd-toc-item">
<a class="bd-toc-link" href="/docs/4.6/about/overview/">
About
</a>
</div>
</nav>
</div>
</div>
<nav class="d-none d-xl-block col-xl-2 bd-toc" aria-label="Secondary navigation">
<nav id="TableOfContents">
<ul>
<li><a href="#containers">Containers</a>
<ul>
<li><a href="#all-in-one">All-in-one</a></li>
<li><a href="#fluid">Fluid</a></li>
<li><a href="#responsive">Responsive</a></li>
</ul>
</li>
<li><a href="#responsive-breakpoints">Responsive breakpoints</a></li>
<li><a href="#z-index">Z-index</a></li>
</ul>
</nav>
</nav>
<main class="col-md-9 col-xl-8 py-md-3 pl-md-5 bd-content" role="main">
<div class="d-md-flex flex-md-row-reverse align-items-center justify-content-between">
<a class="btn btn-sm btn-bd-light my-2 my-md-0" href="https://github.com/twbs/bootstrap/blob/v4-dev/site/content/docs/4.6/layout/overview.md" title="View and edit this file on GitHub" target="_blank" rel="noopener">View on GitHub</a>
<h1 class="bd-title" id="content">Overview</h1>
</div>
<p class="bd-lead">Components and options for laying out your Bootstrap project, including wrapping containers, a powerful grid system, a flexible media object, and responsive utility classes.</p>
<script async src="https://cdn.carbonads.com/carbon.js?serve=CKYIKKJL&placement=getbootstrapcom" id="_carbonads_js"></script>
<h2 id="containers">Containers</h2>
<p>Containers are the most basic layout element in Bootstrap and are <strong>required when using our default grid system</strong>. Containers are used to contain, pad, and (sometimes) center the content within them. While containers <em>can</em> be nested, most layouts do not require a nested container.</p>
<p>Bootstrap comes with three different containers:</p>
<ul>
<li><code>.container</code>, which sets a <code>max-width</code> at each responsive breakpoint</li>
<li><code>.container-fluid</code>, which is <code>width: 100%</code> at all breakpoints</li>
<li><code>.container-{breakpoint}</code>, which is <code>width: 100%</code> until the specified breakpoint</li>
</ul>
<p>The table below illustrates how each container&rsquo;s <code>max-width</code> compares to the original <code>.container</code> and <code>.container-fluid</code> across each breakpoint.</p>
<p>See them in action and compare them in our <a href="/docs/4.6/examples/grid/#containers">Grid example</a>.</p>
<table class="table">
<thead>
<tr>
<th></th>
<th>
Extra small<br>
<span class="font-weight-normal">&lt;576px</span>
</th>
<th>
Small<br>
<span class="font-weight-normal">&ge;576px</span>
</th>
<th>
Medium<br>
<span class="font-weight-normal">&ge;768px</span>
</th>
<th>
Large<br>
<span class="font-weight-normal">&ge;992px</span>
</th>
<th>
Extra large<br>
<span class="font-weight-normal">&ge;1200px</span>
</th>
</tr>
</thead>
<tbody>
<tr>
<td><code>.container</code></td>
<td class="text-muted">100%</td>
<td>540px</td>
<td>720px</td>
<td>960px</td>
<td>1140px</td>
</tr>
<tr>
<td><code>.container-sm</code></td>
<td class="text-muted">100%</td>
<td>540px</td>
<td>720px</td>
<td>960px</td>
<td>1140px</td>
</tr>
<tr>
<td><code>.container-md</code></td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td>720px</td>
<td>960px</td>
<td>1140px</td>
</tr>
<tr>
<td><code>.container-lg</code></td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td>960px</td>
<td>1140px</td>
</tr>
<tr>
<td><code>.container-xl</code></td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td>1140px</td>
</tr>
<tr>
<td><code>.container-fluid</code></td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
<td class="text-muted">100%</td>
</tr>
</tbody>
</table>
<h3 id="all-in-one">All-in-one</h3>
<p>Our default <code>.container</code> class is a responsive, fixed-width container, meaning its <code>max-width</code> changes at each breakpoint.</p>
<div class="highlight"><pre class="chroma"><code class="language-html" data-lang="html"><span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container&#34;</span><span class="p">&gt;</span>
<span class="c">&lt;!-- Content here --&gt;</span>
<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
</code></pre></div><h3 id="fluid">Fluid</h3>
<p>Use <code>.container-fluid</code> for a full width container, spanning the entire width of the viewport.</p>
<div class="highlight"><pre class="chroma"><code class="language-html" data-lang="html"><span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container-fluid&#34;</span><span class="p">&gt;</span>
...
<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
</code></pre></div><h3 id="responsive">Responsive</h3>
<p>Responsive containers are new in Bootstrap v4.4. They allow you to specify a class that is 100% wide until the specified breakpoint is reached, after which we apply <code>max-width</code>s for each of the higher breakpoints. For example, <code>.container-sm</code> is 100% wide to start until the <code>sm</code> breakpoint is reached, where it will scale up with <code>md</code>, <code>lg</code>, and <code>xl</code>.</p>
<div class="highlight"><pre class="chroma"><code class="language-html" data-lang="html"><span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container-sm&#34;</span><span class="p">&gt;</span>100% wide until small breakpoint<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container-md&#34;</span><span class="p">&gt;</span>100% wide until medium breakpoint<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container-lg&#34;</span><span class="p">&gt;</span>100% wide until large breakpoint<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
<span class="p">&lt;</span><span class="nt">div</span> <span class="na">class</span><span class="o">=</span><span class="s">&#34;container-xl&#34;</span><span class="p">&gt;</span>100% wide until extra large breakpoint<span class="p">&lt;/</span><span class="nt">div</span><span class="p">&gt;</span>
</code></pre></div><h2 id="responsive-breakpoints">Responsive breakpoints</h2>
<p>Since Bootstrap is developed to be mobile first, we use a handful of <a href="https://developer.mozilla.org/en-US/docs/Web/CSS/Media_Queries/Using_media_queries">media queries</a> to create sensible breakpoints for our layouts and interfaces. These breakpoints are mostly based on minimum viewport widths and allow us to scale up elements as the viewport changes.</p>
<p>Bootstrap primarily uses the following media query ranges—or breakpoints—in our source Sass files for our layout, grid system, and components.</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="c1">// Extra small devices (portrait phones, less than 576px)
</span><span class="c1">// No media query for `xs` since this is the default in Bootstrap
</span><span class="c1"></span>
<span class="c1">// Small devices (landscape phones, 576px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">576</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Medium devices (tablets, 768px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">768</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Large devices (desktops, 992px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">992</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Extra large devices (large desktops, 1200px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">1200</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
</code></pre></div><p>Since we write our source CSS in Sass, all our media queries are available via Sass mixins:</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="c1">// No media query necessary for xs breakpoint as it&#39;s effectively `@media (min-width: 0) { ... }`
</span><span class="c1"></span><span class="k">@include</span><span class="nd"> media-breakpoint-up</span><span class="p">(</span><span class="n">sm</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-up</span><span class="p">(</span><span class="n">md</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-up</span><span class="p">(</span><span class="n">lg</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-up</span><span class="p">(</span><span class="n">xl</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Example: Hide starting at `min-width: 0`, and then show at the `sm` breakpoint
</span><span class="c1"></span><span class="nc">.custom-class</span> <span class="p">{</span>
<span class="nt">display</span><span class="nd">:</span> <span class="nt">none</span><span class="p">;</span>
<span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-up</span><span class="p">(</span><span class="n">sm</span><span class="p">)</span> <span class="p">{</span>
<span class="nc">.custom-class</span> <span class="p">{</span>
<span class="nt">display</span><span class="nd">:</span> <span class="nt">block</span><span class="p">;</span>
<span class="p">}</span>
<span class="p">}</span>
</code></pre></div><p>We occasionally use media queries that go in the other direction (the given screen size <em>or smaller</em>):</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="c1">// Extra small devices (portrait phones, less than 576px)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">575</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Small devices (landscape phones, less than 768px)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">767</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Medium devices (tablets, less than 992px)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">991</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Large devices (desktops, less than 1200px)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">1199</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Extra large devices (large desktops)
</span><span class="c1">// No media query since the extra-large breakpoint has no upper bound on its width
</span></code></pre></div><div class="bd-callout bd-callout-info">
Note that since browsers do not currently support <a href="https://www.w3.org/TR/mediaqueries-4/#range-context">range context queries</a>, we work around the limitations of <a href="https://www.w3.org/TR/mediaqueries-4/#mq-min-max"><code>min-</code> and <code>max-</code> prefixes</a> and viewports with fractional widths (which can occur under certain conditions on high-dpi devices, for instance) by using values with higher precision for these comparisons.
</div>
<p>Once again, these media queries are also available via Sass mixins:</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="k">@include</span><span class="nd"> media-breakpoint-down</span><span class="p">(</span><span class="n">xs</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-down</span><span class="p">(</span><span class="n">sm</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-down</span><span class="p">(</span><span class="n">md</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-down</span><span class="p">(</span><span class="n">lg</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// No media query necessary for xl breakpoint as it has no upper bound on its width
</span><span class="c1"></span>
<span class="c1">// Example: Style from medium breakpoint and down
</span><span class="c1"></span><span class="k">@include</span><span class="nd"> media-breakpoint-down</span><span class="p">(</span><span class="n">md</span><span class="p">)</span> <span class="p">{</span>
<span class="nc">.custom-class</span> <span class="p">{</span>
<span class="nt">display</span><span class="nd">:</span> <span class="nt">block</span><span class="p">;</span>
<span class="p">}</span>
<span class="p">}</span>
</code></pre></div><p>There are also media queries and mixins for targeting a single segment of screen sizes using the minimum and maximum breakpoint widths.</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="c1">// Extra small devices (portrait phones, less than 576px)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">575</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Small devices (landscape phones, 576px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">576</span><span class="kt">px</span><span class="p">)</span> <span class="ow">and</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">767</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Medium devices (tablets, 768px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">768</span><span class="kt">px</span><span class="p">)</span> <span class="ow">and</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">991</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Large devices (desktops, 992px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">992</span><span class="kt">px</span><span class="p">)</span> <span class="ow">and</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">1199</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="c1">// Extra large devices (large desktops, 1200px and up)
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">1200</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
</code></pre></div><p>These media queries are also available via Sass mixins:</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="k">@include</span><span class="nd"> media-breakpoint-only</span><span class="p">(</span><span class="n">xs</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-only</span><span class="p">(</span><span class="n">sm</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-only</span><span class="p">(</span><span class="n">md</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-only</span><span class="p">(</span><span class="n">lg</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
<span class="k">@include</span><span class="nd"> media-breakpoint-only</span><span class="p">(</span><span class="n">xl</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
</code></pre></div><p>Similarly, media queries may span multiple breakpoint widths:</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="c1">// Example
</span><span class="c1">// Apply styles starting from medium devices and up to extra large devices
</span><span class="c1"></span><span class="k">@media</span> <span class="p">(</span><span class="no">min-width</span><span class="o">:</span> <span class="mi">768</span><span class="kt">px</span><span class="p">)</span> <span class="ow">and</span> <span class="p">(</span><span class="no">max-width</span><span class="o">:</span> <span class="mi">1199</span><span class="mf">.98</span><span class="kt">px</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
</code></pre></div><p>The Sass mixin for targeting the same screen size range would be:</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="k">@include</span><span class="nd"> media-breakpoint-between</span><span class="p">(</span><span class="n">md</span><span class="o">,</span> <span class="n">xl</span><span class="p">)</span> <span class="p">{</span> <span class="nc">...</span> <span class="p">}</span>
</code></pre></div><h2 id="z-index">Z-index</h2>
<p>Several Bootstrap components utilize <code>z-index</code>, the CSS property that helps control layout by providing a third axis to arrange content. We utilize a default z-index scale in Bootstrap that&rsquo;s been designed to properly layer navigation, tooltips and popovers, modals, and more.</p>
<p>These higher values start at an arbitrary number, high and specific enough to ideally avoid conflicts. We need a standard set of these across our layered components—tooltips, popovers, navbars, dropdowns, modals—so we can be reasonably consistent in the behaviors. There&rsquo;s no reason we couldn&rsquo;t have used <code>100</code>+ or <code>500</code>+.</p>
<p>We don&rsquo;t encourage customization of these individual values; should you change one, you likely need to change them all.</p>
<div class="highlight"><pre class="chroma"><code class="language-scss" data-lang="scss"><span class="nv">$zindex-dropdown</span><span class="o">:</span> <span class="mi">1000</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-sticky</span><span class="o">:</span> <span class="mi">1020</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-fixed</span><span class="o">:</span> <span class="mi">1030</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-modal-backdrop</span><span class="o">:</span> <span class="mi">1040</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-modal</span><span class="o">:</span> <span class="mi">1050</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-popover</span><span class="o">:</span> <span class="mi">1060</span> <span class="nv">!default</span><span class="p">;</span>
<span class="nv">$zindex-tooltip</span><span class="o">:</span> <span class="mi">1070</span> <span class="nv">!default</span><span class="p">;</span>
</code></pre></div><p>To handle overlapping borders within components (e.g., buttons and inputs in input groups), we use low single digit <code>z-index</code> values of <code>1</code>, <code>2</code>, and <code>3</code> for default, hover, and active states. On hover/focus/active, we bring a particular element to the forefront with a higher <code>z-index</code> value to show their border over the sibling elements.</p>
</main>
</div>
</div>
<script src="https://code.jquery.com/jquery-3.5.1.slim.min.js" integrity="sha384-DfXdz2htPH0lsSSs5nCTpuj/zy4C+OGpamoFVy38MVBnE+IbbVYUew+OrCXaRkfj" crossorigin="anonymous"></script>
<script>window.jQuery || document.write('<script src="/docs/4.6/assets/js/vendor/jquery.slim.min.js"><\/script>')</script>
<script src="/docs/4.6/dist/js/bootstrap.bundle.min.js" integrity="sha384-Piv4xVNRyMGpqkS2by6br4gNJ7DXjqk09RmUpJ8jgGtD7zP9yug3goQfGII0yAns" crossorigin="anonymous"></script>
<script src="https://cdn.jsdelivr.net/npm/docsearch.js@2/dist/cdn/docsearch.min.js"></script>
<script src="/docs/4.6/assets/js/docs.min.js"></script>
</body>
</html>
Reference in New Issue Copy Permalink