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<!doctype html>
<html lang="en">
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type">
<title>CSS Grid Layout Module Level 1</title>
<meta content="revising" name="csswg-work-status">
<meta content="WD" name="w3c-status">
<link href="../default.css" rel="stylesheet" type="text/css">
<link href="../csslogo.ico" rel="shortcut icon" type="image/x-icon">
<link href="https://www.w3.org/StyleSheets/TR/W3C-WD" rel="stylesheet" type="text/css">
<meta content="Bikeshed 1.0.0" name="generator">
<script defer="" src="//test.csswg.org/harness/annotate.js#css-grid-1_dev/css-grid-1" type="text/javascript"></script>
<style type="text/css">
.example {
clear:both
}
.pseudo-code {
font-family:monospace
}
.pseudo-code > ol {
list-style-type:decimal
}
.pseudo-code > ol > li > ol {
list-style-type:lower-latin
}
.pseudo-code > ol > li > ol > li > ol {
list-style-type:lower-roman
}
.pseudo-code ul {
list-style-type:disc
}
dd > p:nth-child(1) {
margin-top:0
}
dd:last-child {
margin-bottom: 0;
}
dl.phase {
padding-left: .5em;
border-left: .5em #e0e0e0 solid;
}
#grid-property-breakdown tr:nth-child(3) td {
width: 25%;
border-style: solid;
}
</style>
<style>.highlight .hll { background-color: #ffffcc }
.highlight { background: #ffffff; }
.highlight .c { color: #708090 } /* Comment */
.highlight .k { color: #990055 } /* Keyword */
.highlight .l { color: #669900 } /* Literal */
.highlight .n { color: #0077aa } /* Name */
.highlight .o { color: #999999 } /* Operator */
.highlight .p { color: #999999 } /* Punctuation */
.highlight .cm { color: #708090 } /* Comment.Multiline */
.highlight .cp { color: #708090 } /* Comment.Preproc */
.highlight .c1 { color: #708090 } /* Comment.Single */
.highlight .cs { color: #708090 } /* Comment.Special */
.highlight .kc { color: #990055 } /* Keyword.Constant */
.highlight .kd { color: #990055 } /* Keyword.Declaration */
.highlight .kn { color: #990055 } /* Keyword.Namespace */
.highlight .kp { color: #990055 } /* Keyword.Pseudo */
.highlight .kr { color: #990055 } /* Keyword.Reserved */
.highlight .kt { color: #990055 } /* Keyword.Type */
.highlight .ld { color: #669900 } /* Literal.Date */
.highlight .m { color: #990055 } /* Literal.Number */
.highlight .s { color: #669900 } /* Literal.String */
.highlight .na { color: #0077aa } /* Name.Attribute */
.highlight .nc { color: #0077aa } /* Name.Class */
.highlight .no { color: #0077aa } /* Name.Constant */
.highlight .nd { color: #0077aa } /* Name.Decorator */
.highlight .ni { color: #0077aa } /* Name.Entity */
.highlight .ne { color: #0077aa } /* Name.Exception */
.highlight .nf { color: #0077aa } /* Name.Function */
.highlight .nl { color: #0077aa } /* Name.Label */
.highlight .nn { color: #0077aa } /* Name.Namespace */
.highlight .py { color: #0077aa } /* Name.Property */
.highlight .nt { color: #0077aa } /* Name.Tag */
.highlight .nv { color: #0077aa } /* Name.Variable */
.highlight .ow { color: #999999 } /* Operator.Word */
.highlight .mb { color: #990055 } /* Literal.Number.Bin */
.highlight .mf { color: #990055 } /* Literal.Number.Float */
.highlight .mh { color: #990055 } /* Literal.Number.Hex */
.highlight .mi { color: #990055 } /* Literal.Number.Integer */
.highlight .mo { color: #990055 } /* Literal.Number.Oct */
.highlight .sb { color: #669900 } /* Literal.String.Backtick */
.highlight .sc { color: #669900 } /* Literal.String.Char */
.highlight .sd { color: #669900 } /* Literal.String.Doc */
.highlight .s2 { color: #669900 } /* Literal.String.Double */
.highlight .se { color: #669900 } /* Literal.String.Escape */
.highlight .sh { color: #669900 } /* Literal.String.Heredoc */
.highlight .si { color: #669900 } /* Literal.String.Interpol */
.highlight .sx { color: #669900 } /* Literal.String.Other */
.highlight .sr { color: #669900 } /* Literal.String.Regex */
.highlight .s1 { color: #669900 } /* Literal.String.Single */
.highlight .ss { color: #669900 } /* Literal.String.Symbol */
.highlight .vc { color: #0077aa } /* Name.Variable.Class */
.highlight .vg { color: #0077aa } /* Name.Variable.Global */
.highlight .vi { color: #0077aa } /* Name.Variable.Instance */
.highlight .il { color: #990055 } /* Literal.Number.Integer.Long */
.highlight { background: hsl(24, 20%, 95%); }
code.highlight { padding: .1em; border-radius: .3em; }
pre.highlight, pre > code.highlight { display: block; padding: 1em; margin: .5em 0; overflow: auto; border-radius: 0; }
</style>
</head>
<body class="h-entry">
<div class="head">
<p data-fill-with="logo"><a class="logo" href="http://www.w3.org/">
<img alt="W3C" height="48" src="https://www.w3.org/Icons/w3c_home" width="72">
</a>
</p>
<h1 class="p-name no-ref" id="title">CSS Grid Layout Module Level 1</h1>
<h2 class="no-num no-toc no-ref heading settled" id="subtitle"><span class="content">W3C Working Draft,
<time class="dt-updated" datetime="2015-08-06">6 August 2015</time></span></h2>
<div data-fill-with="spec-metadata">
<dl>
<dt>This version:
<dd><a class="u-url" href="http://www.w3.org/TR/2015/WD-css-grid-1-20150806/">http://www.w3.org/TR/2015/WD-css-grid-1-20150806/</a>
<dt>Latest version:
<dd><a href="http://www.w3.org/TR/css-grid-1/">http://www.w3.org/TR/css-grid-1/</a>
<dt>Editor's Draft:
<dd><a href="http://dev.w3.org/csswg/css-grid/">http://dev.w3.org/csswg/css-grid/</a>
<dt>Previous Versions:
<dd><a href="http://www.w3.org/TR/2014/WD-css-grid-1-20140513/" rel="previous">http://www.w3.org/TR/2014/WD-css-grid-1-20140513/</a>
<dd><a href="http://www.w3.org/TR/2014/WD-css-grid-1-20140123/" rel="previous">http://www.w3.org/TR/2014/WD-css-grid-1-20140123/</a>
<dd><a href="http://www.w3.org/TR/2013/WD-css3-grid-layout-20130402/" rel="previous">http://www.w3.org/TR/2013/WD-css3-grid-layout-20130402/</a>
<dd><a href="http://www.w3.org/TR/2012/WD-css3-grid-layout-20121106/" rel="previous">http://www.w3.org/TR/2012/WD-css3-grid-layout-20121106/</a>
<dt>Feedback:
<dd><span><a href="mailto:www-style@w3.org?subject=%5Bcss-grid%5D%20YOUR%20TOPIC%20HERE">www-style@w3.org</a> with subject line “<kbd>[css-grid] <var>… message topic …</var></kbd>” (<a href="http://lists.w3.org/Archives/Public/www-style/" rel="discussion">archives</a>)</span>
<dt>Test Suite:
<dd><a href="http://test.csswg.org/suites/css-grid-1_dev/nightly-unstable/">http://test.csswg.org/suites/css-grid-1_dev/nightly-unstable/</a>
<dt>Issue Tracking:
<dd><a href="https://github.com/w3c/csswg-drafts/issues/">GitHub</a>
<dd><a href="#issues-index">Inline In Spec</a>
<dt class="editor">Editors:
<dd class="editor p-author h-card vcard"><a class="p-name fn u-url url" href="http://www.xanthir.com/contact/">Tab Atkins Jr.</a> (<span class="p-org org">Google</span>)
<dd class="editor p-author h-card vcard"><a class="p-name fn u-url url" href="http://fantasai.inkedblade.net/contact">fantasai</a> (<span class="p-org org">Mozilla</span>)
<dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:ratan@microsoft.com">Rossen Atanassov</a> (<span class="p-org org">Microsoft</span>)
<dt>Former Editors:
<dd>
<dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:alexmog@microsoft.com">Alex Mogilevsky</a> (<span class="p-org org">Microsoft Corporation</span>)
<dd>
<dd class="editor p-author h-card vcard"><a class="p-name fn u-email email" href="mailto:pcupp@microsoft.com">Phil Cupp</a> (<span class="p-org org">Microsoft Corporation</span>)
<dt>Issues list:
<dd><span><a href="https://www.w3.org/Bugs/Public/buglist.cgi?product=CSS&component=Grid+Layout&bug_status=NEW&bug_status=ASSIGNED&bug_status=REOPENED">In Bugzilla</a></span>
</dl>
</div>
<div data-fill-with="warning"></div>
<p class="copyright" data-fill-with="copyright"><a href="http://www.w3.org/Consortium/Legal/ipr-notice#Copyright">Copyright</a> © 2015 <a href="http://www.w3.org/"><abbr title="World Wide Web Consortium">W3C</abbr></a><sup>®</sup> (<a href="http://www.csail.mit.edu/"><abbr title="Massachusetts Institute of Technology">MIT</abbr></a>, <a href="http://www.ercim.eu/"><abbr title="European Research Consortium for Informatics and Mathematics">ERCIM</abbr></a>, <a href="http://www.keio.ac.jp/">Keio</a>, <a href="http://ev.buaa.edu.cn/">Beihang</a>). W3C <a href="http://www.w3.org/Consortium/Legal/ipr-notice#Legal_Disclaimer">liability</a>, <a href="http://www.w3.org/Consortium/Legal/ipr-notice#W3C_Trademarks">trademark</a> and <a href="http://www.w3.org/Consortium/Legal/copyright-documents">document use</a> rules apply.
</p>
<hr title="Separator for header">
</div>
<h2 class="no-num no-toc no-ref heading settled" id="abstract"><span class="content">Abstract</span></h2>
<div class="p-summary" data-fill-with="abstract">
<p>This CSS module defines a two-dimensional grid-based layout system, optimized for user interface design. In the grid layout model, the children of a grid container can be positioned into arbitrary slots in a flexible or fixed predefined layout grid.</p>
<a href="http://www.w3.org/TR/CSS/">CSS</a> is a language for describing the rendering of structured documents
(such as HTML and XML)
on screen, on paper, in speech, etc.</div>
<h2 class="no-num no-toc no-ref heading settled" id="status"><span class="content">Status of this document</span></h2>
<div data-fill-with="status">
<p><em>This section describes the status of this document at the time of
its publication. Other documents may supersede this document. A list of
current W3C publications and the latest revision of this technical report
can be found in the <a href="http://www.w3.org/TR/">W3C technical reports
index at http://www.w3.org/TR/.</a></em>
</p>
<p>Publication as a Working Draft does not imply endorsement by the W3C
Membership. This is a draft document and may be updated, replaced or
obsoleted by other documents at any time. It is inappropriate to cite this
document as other than work in progress.
</p>
<p>The (<a href="http://lists.w3.org/Archives/Public/www-style/">archived</a>) public
mailing list <a href="mailto:www-style@w3.org">www-style@w3.org</a> (see
<a href="http://www.w3.org/Mail/Request">instructions</a>) is preferred
for discussion of this specification. When sending e-mail, please put the
text “css-grid” in the subject, preferably like this:
“[css-grid] <em>…summary of comment…</em>”
</p>
<p>This document was produced by the <a href="http://www.w3.org/Style/CSS/members">CSS Working Group</a> (part of
the <a href="http://www.w3.org/Style/">Style Activity</a>).
</p>
<p>This document was produced by a group operating under the <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/">5 February
2004 W3C Patent Policy</a>. W3C maintains a <a href="http://www.w3.org/2004/01/pp-impl/32061/status" rel="disclosure">public list of any patent disclosures</a> made in
connection with the deliverables of the group; that page also includes
instructions for disclosing a patent. An individual who has actual
knowledge of a patent which the individual believes contains <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#def-essential">Essential
Claim(s)</a> must disclose the information in accordance with <a href="http://www.w3.org/Consortium/Patent-Policy-20040205/#sec-Disclosure">section
6 of the W3C Patent Policy</a>.</p>
<p>This document is governed by the <a href="http://www.w3.org/2014/Process-20140801/" id="w3c_process_revision">1 August 2014 W3C Process Document</a>.
</p>
<p>
</p></div>
<div data-fill-with="at-risk">
<p>The following features are at-risk, and may be dropped during the CR period:
</p>
<ul>
<li>the <a class="css" data-link-type="maybe" href="#valdef-grid-template-rows-subgrid">subgrid</a> value of <a class="property" data-link-type="propdesc" href="#propdef-grid-template-columns">grid-template-columns</a> and <a class="property" data-link-type="propdesc" href="#propdef-grid-template-rows">grid-template-rows</a>, and its component parts individually
</ul>
<p>“At-risk” is a W3C Process term-of-art, and does not necessarily imply that the feature is in danger of being dropped or delayed. It means that the WG believes the feature may have difficulting being interoperably implemented in a timely manner, and marking it as such allows the WG to drop the feature if necessary when transitioning to the Proposed Rec stage, without having to publish a new Candidate Rec without the feature first.</p></div>
<h2 class="no-num no-toc no-ref heading settled" id="contents"><span class="content">Table of Contents</span></h2>
<div data-fill-with="table-of-contents" role="navigation">
<ul class="toc" role="directory">
<li><a href="#intro"><span class="secno">1</span> <span class="content">
Introduction and Overview</span></a>
<ul class="toc">
<li><a href="#background"><span class="secno">1.1</span> <span class="content">
Background and Motivation</span></a>
<li><a href="#adapting-to-available-space"><span class="secno">1.2</span> <span class="content">
Adapting Layouts to Available Space</span></a>
<li><a href="#source-independence"><span class="secno">1.3</span> <span class="content">
Source-Order Independence</span></a>
<li><a href="#grid-layering"><span class="secno">1.4</span> <span class="content">
Grid Layering of Elements</span></a>
</ul>
<li><a href="#grid-concepts"><span class="secno">2</span> <span class="content">
Grid Layout Concepts and Terminology</span></a>
<ul class="toc">
<li><a href="#grid-track-concept"><span class="secno">2.1</span> <span class="content">
Grid Tracks and Cells</span></a>
<li><a href="#grid-line-concept"><span class="secno">2.2</span> <span class="content">
Grid Lines</span></a>
<li><a href="#grid-area-concept"><span class="secno">2.3</span> <span class="content">
Grid Areas</span></a>
</ul>
<li><a href="#grid-model"><span class="secno">3</span> <span class="content">
Grid Containers</span></a>
<ul class="toc">
<li><a href="#grid-containers"><span class="secno">3.1</span> <span class="content">
Establishing Grid Containers: the <span class="css">grid</span> and <span class="css">inline-grid</span> <span class="property">display</span> values</span></a>
<li><a href="#intrinsic-sizes"><span class="secno">3.2</span> <span class="content">
Sizing Grid Containers</span></a>
</ul>
<li><a href="#grid-items"><span class="secno">4</span> <span class="content">
Grid Items</span></a>
<ul class="toc">
<li><a href="#visibility-collapse"><span class="secno">4.1</span> <span class="content">
Collapsed Grid Items: the <span class="property">visibility</span> property</span></a>
<li><a href="#order-property"><span class="secno">4.2</span> <span class="content">
Reordered Grid Items: the <span class="property">order</span> property</span></a>
<li><a href="#z-order"><span class="secno">4.3</span> <span class="content">
Z-axis Ordering: the <span class="property">z-index</span> property</span></a>
<li><a href="#min-size-auto"><span class="secno">4.4</span> <span class="content">
Implied Minimum Size of Grid Items</span></a>
</ul>
<li><a href="#grid-definition"><span class="secno">5</span> <span class="content">
The Explicit Grid</span></a>
<ul class="toc">
<li><a href="#track-sizing"><span class="secno">5.1</span> <span class="content">
Track Sizing: the <span class="property">grid-template-rows</span> and <span class="property">grid-template-columns</span> properties</span></a>
<ul class="toc">
<li><a href="#named-lines"><span class="secno">5.1.1</span> <span class="content">
Named Grid Lines: the <span class="css">(<span class="production"><custom-ident></span>*)</span> syntax</span></a>
<li><a href="#repeat-notation"><span class="secno">5.1.2</span> <span class="content">
Repeating Rows and Columns: the <span class="css">repeat()</span> notation</span></a>
<ul class="toc">
<li><a href="#repeat-auto"><span class="secno">5.1.2.1</span> <span class="content">
Repeat-to-fill</span></a>
</ul>
<li><a href="#fr-unit"><span class="secno">5.1.3</span> <span class="content">
Flexible Lengths: the <span class="css">fr</span> unit</span></a>
<li><a href="#subgrids"><span class="secno">5.1.4</span> <span class="content">
Subgrids: the <span class="css">subgrid</span> keyword</span></a>
<li><a href="#resolved-track-list"><span class="secno">5.1.5</span> <span class="content">
Resolved Values</span></a>
</ul>
<li><a href="#grid-template-areas-property"><span class="secno">5.2</span> <span class="content">
Named Areas: the <span class="property">grid-template-areas</span> property</span></a>
<ul class="toc">
<li><a href="#implicit-named-lines"><span class="secno">5.2.1</span> <span class="content">
Implicit Named Lines</span></a>
<li><a href="#implicit-named-areas"><span class="secno">5.2.2</span> <span class="content">
Implicit Named Areas</span></a>
</ul>
<li><a href="#explicit-grid-shorthand"><span class="secno">5.3</span> <span class="content">
Explicit Grid Shorthand: the <span class="property">grid-template</span> property</span></a>
</ul>
<li><a href="#implicit-grids"><span class="secno">6</span> <span class="content">
The Implicit Grid</span></a>
<ul class="toc">
<li><a href="#auto-tracks"><span class="secno">6.1</span> <span class="content">
Sizing Auto-generated Rows and Columns: the <span class="property">grid-auto-rows</span> and <span class="property">grid-auto-columns</span> properties</span></a>
<li><a href="#grid-auto-flow-property"><span class="secno">6.2</span> <span class="content">
<span>Automatic Placement</span>: the <span class="property">grid-auto-flow</span> property</span></a>
</ul>
<li><a href="#grid-shorthand"><span class="secno">7</span> <span class="content">
Grid Definition Shorthand: the <span class="property">grid</span> property</span></a>
<li><a href="#overlarge-grids"><span class="secno">8</span> <span class="content">
Clamping Overlarge Grids</span></a>
<li><a href="#placement"><span class="secno">9</span> <span class="content">
Placing Grid Items</span></a>
<ul class="toc">
<li><a href="#common-uses"><span class="secno">9.1</span> <span class="content">
Common Patterns for Grid Placement</span></a>
<ul class="toc">
<li><a href="#common-uses-named-areas"><span class="secno">9.1.1</span> <span class="content">
Named Areas</span></a>
<li><a href="#common-uses-numeric"><span class="secno">9.1.2</span> <span class="content">
Numeric Indexes and Spans</span></a>
<li><a href="#common-uses-named-lines"><span class="secno">9.1.3</span> <span class="content">
Named Lines and Spans</span></a>
<li><a href="#common-uses-auto-placement"><span class="secno">9.1.4</span> <span class="content">
Auto Placement</span></a>
<li><a href="#common-uses-auto-sizing"><span class="secno">9.1.5</span> <span class="content">
Auto Sizing Subgrids</span></a>
</ul>
<li><a href="#line-placement"><span class="secno">9.2</span> <span class="content">
Line-based Placement: the <span class="property">grid-row-start</span>, <span class="property">grid-column-start</span>, <span class="property">grid-row-end</span>, and <span class="property">grid-column-end</span> properties</span></a>
<ul class="toc">
<li><a href="#grid-placement-errors"><span class="secno">9.2.1</span> <span class="content">
Grid Placement Conflict Handling</span></a>
</ul>
<li><a href="#placement-shorthands"><span class="secno">9.3</span> <span class="content">
Placement Shorthands: the <span class="property">grid-column</span>, <span class="property">grid-row</span>, and <span class="property">grid-area</span> properties</span></a>
<li><a href="#auto-placement-algo"><span class="secno">9.4</span> <span class="content">
Grid Item Placement Algorithm</span></a>
</ul>
<li><a href="#abspos"><span class="secno">10</span> <span class="content">
Absolute Positioning</span></a>
<ul class="toc">
<li><a href="#abspos-items"><span class="secno">10.1</span> <span class="content">
With a Grid Container as Containing Block</span></a>
<li><a href="#static-position"><span class="secno">10.2</span> <span class="content">
With a Grid Container as Parent</span></a>
</ul>
<li><a href="#alignment"><span class="secno">11</span> <span class="content">
Alignment and Spacing</span></a>
<ul class="toc">
<li><a href="#gutters"><span class="secno">11.1</span> <span class="content">
Gutters: the <span class="property">column-gap</span>, <span class="property">row-gap</span>, and <span class="property">grid-gap</span> properties</span></a>
<li><a href="#auto-margins"><span class="secno">11.2</span> <span class="content">
Aligning with <span>auto</span> margins</span></a>
<li><a href="#row-align"><span class="secno">11.3</span> <span class="content">
Row-axis Alignment: the <span class="property">justify-self</span> and <span class="property">justify-items</span> properties</span></a>
<li><a href="#column-align"><span class="secno">11.4</span> <span class="content">
Column-axis Alignment: the <span class="property">align-self</span> and <span class="property">align-items</span> properties</span></a>
<li><a href="#grid-align"><span class="secno">11.5</span> <span class="content">
Aligning the Grid: the <span class="property">justify-content</span> and <span class="property">align-content</span> properties</span></a>
<li><a href="#grid-baselines"><span class="secno">11.6</span> <span class="content">
Grid Baselines</span></a>
</ul>
<li><a href="#layout-algorithm"><span class="secno">12</span> <span class="content">
Grid Sizing</span></a>
<ul class="toc">
<li><a href="#algo-overview"><span class="secno">12.1</span> <span class="content">
Grid Sizing Algorithm</span></a>
<li><a href="#algo-terms"><span class="secno">12.2</span> <span class="content">
Track Sizing Terminology</span></a>
<li><a href="#algo-track-sizing"><span class="secno">12.3</span> <span class="content">
Track Sizing Algorithm</span></a>
<li><a href="#algo-init"><span class="secno">12.4</span> <span class="content">
Initialize Track Sizes</span></a>
<li><a href="#algo-content"><span class="secno">12.5</span> <span class="content">
Resolve Intrinsic Track Sizes</span></a>
<li><a href="#algo-grow-tracks"><span class="secno">12.6</span> <span class="content">
Maximize Tracks</span></a>
<li><a href="#algo-flex-tracks"><span class="secno">12.7</span> <span class="content">
Stretch Flexible Tracks</span></a>
<ul class="toc">
<li><a href="#algo-find-fr-size"><span class="secno">12.7.1</span> <span class="content">
Find the Size of an <span class="css">fr</span></span></a>
</ul>
</ul>
<li><a href="#pagination"><span class="secno">13</span> <span class="content">
Fragmenting Grid Layout</span></a>
<ul class="toc">
<li><a href="#fragmentation-alg"><span class="secno">13.1</span> <span class="content">
Sample Fragmentation Algorithm</span></a>
</ul>
<li><a href="#acks"><span class="secno"></span> <span class="content">
Acknowledgements</span></a>
<li><a href="#changes"><span class="secno"></span> <span class="content">
Changes</span></a>
<li><a href="#translated-algo"><span class="secno"></span> <span class="content">
Appendix A: Translated Layout Algorithm</span></a>
<li><a href="#conformance"><span class="secno"></span> <span class="content">
Conformance</span></a>
<ul class="toc">
<li><a href="#conventions"><span class="secno"></span> <span class="content">
Document conventions</span></a>
<li><a href="#conformance-classes"><span class="secno"></span> <span class="content">
Conformance classes</span></a>
<li><a href="#partial"><span class="secno"></span> <span class="content">
Partial implementations</span></a>
<li><a href="#experimental"><span class="secno"></span> <span class="content">
Experimental implementations</span></a>
<li><a href="#testing"><span class="secno"></span> <span class="content">
Non-experimental implementations</span></a>
</ul>
<li><a href="#index"><span class="secno"></span> <span class="content">Index</span></a>
<ul class="toc">
<li><a href="#index-defined-here"><span class="secno"></span> <span class="content">Terms defined by this specification</span></a>
<li><a href="#index-defined-elsewhere"><span class="secno"></span> <span class="content">Terms defined by reference</span></a>
</ul>
<li><a href="#references"><span class="secno"></span> <span class="content">References</span></a>
<ul class="toc">
<li><a href="#normative"><span class="secno"></span> <span class="content">Normative References</span></a>
<li><a href="#informative"><span class="secno"></span> <span class="content">Informative References</span></a>
</ul>
<li><a href="#property-index"><span class="secno"></span> <span class="content">Property Index</span></a>
<li><a href="#issues-index"><span class="secno"></span> <span class="content">Issues Index</span></a>
</ul></div>
<main>
<h2 class="heading settled" data-level="1" id="intro"><span class="secno">1. </span><span class="content">
Introduction and Overview</span><a class="self-link" href="#intro"></a></h2>
<p>Grid layout contains features targeted at web application authors.
The grid can be used to achieve many different layouts.
It excels at dividing up space for major regions of an application,
or defining the relationship in terms of size, position, and layer
between parts of a control built from HTML primitives.</p>
<p>Like tables,
grid layout enables an author to align elements into columns and rows,
but unlike tables,
grid layout doesn’t have content structure,
and thus enables a wide variety of layouts not possible with tables.
For example, the children of a grid container can position themselves
such that they overlap and layer similar to positioned elements.</p>
<p>In addition, the absence of content structure in grid layout helps to manage changes to layout
by using fluid and source order independent layout techniques.
By combining media queries with the CSS properties that control layout of the grid container and its children,
authors can adapt their layout to changes in device form factors, orientation, and available space,
without needing to alter the semantic nature of their content.</p>
<h3 class="heading settled" data-level="1.1" id="background"><span class="secno">1.1. </span><span class="content">
Background and Motivation</span><a class="self-link" href="#background"></a></h3>
<figure class="sidefigure">
<img alt="Image: Application layout example requiring horizontal and vertical alignment." class="figure" src="images/basic-form.png">
<figcaption>Application layout example requiring horizontal and vertical alignment.</figcaption>
</figure>
<p>As websites evolved from simple documents into complex, interactive applications,
tools for document layout, e.g. floats,
were not necessarily well suited for application layout.
By using a combination of tables, JavaScript, or careful measurements on floated elements,
authors discovered workarounds to achieve desired layouts.
Layouts that adapted to the available space were often brittle
and resulted in counter-intuitive behavior as space became constrained.
As an alternative, authors of many web applications opted for a fixed layout
that cannot take advantage of changes in the available rendering space on a screen.</p>
<p>The capabilities of grid layout address these problems.
It provides a mechanism for authors to divide available space for layout into columns and rows
using a set of predictable sizing behaviors.
Authors can then precisely position and size the building block elements of their application
by into <a data-link-type="dfn" href="#grid-area">grid areas</a> defined by these columns and rows.
Figure 1 illustrates a basic layout which can be achieved with grid layout.</p>
<h3 class="heading settled" data-level="1.2" id="adapting-to-available-space"><span class="secno">1.2. </span><span class="content">
Adapting Layouts to Available Space</span><a class="self-link" href="#adapting-to-available-space"></a></h3>
<figure class="sidefigure">
<img alt="Image: Five grid items arranged according to content size and available space." src="images/game-smaller.png">
<figcaption>Five grid items arranged according to content size and available space.</figcaption>
</figure>
<figure class="sidefigure">
<img alt="Image: Growth in the grid due to an increase in available space." src="images/game-larger.png">
<figcaption>Growth in the grid due to an increase in available space.</figcaption>
</figure>
<p>Grid layout can be used to intelligently reflow elements within a webpage.
Figure 2 represents a game with five major areas in the layout:
the game title, stats area, game board, score area, and control area.
The author’s intent is to divide the space for the game such that:</p>
<ul>
<li>
The stats area always appears immediately under the game title.
<li>
The game board appears to the right of the stats and title.
<li>
The top of the game title and the game board should always align.
<li>
The bottom of the game board and the stats area align when the game has reached its minimum height,
but otherwise the game board will stretch to take advantage of all the screen real-estate available to it.
<li>
The score area should align into the column created by the game and stats area,
while the controls are centered under the board.
</ul>
<p>As an alternative to using script to control the absolute position, width, and height of all elements,
the author can use grid layout,
as shown in Figure 3.
The following example shows how an author might achieve all the sizing, placement, and alignment rules declaratively.</p>
<p>Note that there are multiple ways to specify the structure of the grid
and to position and size <a data-link-type="dfn" href="#grid-item">grid items</a>,
each optimized for different scenarios.
This example illustrates one that an author may use to define the position and space for each <a data-link-type="dfn" href="#grid-item">grid item</a>
using the <a class="property" data-link-type="propdesc" href="#propdef-grid-template-rows">grid-template-rows</a> and <a class="property" data-link-type="propdesc" href="#propdef-grid-template-columns">grid-template-columns</a> properties on the <a data-link-type="dfn" href="#grid-container">grid container</a>,
and the <a class="property" data-link-type="propdesc" href="#propdef-grid-row">grid-row</a> and <a class="property" data-link-type="propdesc" href="#propdef-grid-column">grid-column</a> properties on each <a data-link-type="dfn" href="#grid-item">grid item</a>.</p>
<div class="example" id="example-8bec48fd"><a class="self-link" href="#example-8bec48fd"></a>
<pre class="lang-css highlight" highlight="css"><span class="nf">#grid</span> <span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="n">grid</span><span class="p">;</span>
<span class="c">/* Two columns: the first sized to content, the second receives</span>
<span class="c"> * the remaining space, but is never smaller than the minimum</span>
<span class="c"> * size of the board or the game controls, which occupy this</span>
<span class="c"> * column. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">columns</span><span class="o">:</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">);</span>
<span class="c">/* Three rows: the first and last sized to content, the middle</span>
<span class="c"> * row receives the remaining space, but is never smaller than</span>
<span class="c"> * the minimum height of the board or stats areas. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">rows</span><span class="o">:</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">)</span> <span class="k">auto</span>
<span class="p">}</span>
<span class="c">/* Each part of the game is positioned between grid lines by</span>
<span class="c"> * referencing the starting grid line and then specifying, if more</span>
<span class="c"> * than one, the number of rows or columns spanned to determine</span>
<span class="c"> * the ending grid line, which establishes bounds for the part. */</span>
<span class="nf">#title</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="m">1</span><span class="p">;</span> <span class="n">grid</span><span class="o">-</span><span class="n">row</span><span class="o">:</span> <span class="m">1</span> <span class="p">}</span>
<span class="nf">#score</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="m">1</span><span class="p">;</span> <span class="n">grid</span><span class="o">-</span><span class="n">row</span><span class="o">:</span> <span class="m">3</span> <span class="p">}</span>
<span class="nf">#stats</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="m">1</span><span class="p">;</span> <span class="n">grid</span><span class="o">-</span><span class="n">row</span><span class="o">:</span> <span class="m">2</span><span class="p">;</span> <span class="n">align</span><span class="o">-</span><span class="n">self</span><span class="o">:</span> <span class="n">start</span> <span class="p">}</span>
<span class="nf">#board</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="m">2</span><span class="p">;</span> <span class="n">grid</span><span class="o">-</span><span class="n">row</span><span class="o">:</span> <span class="m">1</span> <span class="o">/</span> <span class="n">span</span> <span class="m">2</span><span class="p">;</span> <span class="p">}</span>
<span class="nf">#controls</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="m">2</span><span class="p">;</span> <span class="n">grid</span><span class="o">-</span><span class="n">row</span><span class="o">:</span> <span class="m">3</span><span class="p">;</span> <span class="k">justify</span><span class="o">-</span><span class="n">self</span><span class="o">:</span> <span class="k">center</span> <span class="p">}</span></pre>
<pre class="lang-markup highlight" highlight="markup"><span class="nt"><div</span> <span class="na">id=</span><span class="s">"grid"</span><span class="nt">></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"title"</span><span class="nt">></span>Game Title<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"score"</span><span class="nt">></span>Score<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"stats"</span><span class="nt">></span>Stats<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"board"</span><span class="nt">></span>Board<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"controls"</span><span class="nt">></span>Controls<span class="nt"></div></span>
<span class="nt"></div></span></pre>
</div>
<h3 class="heading settled" data-level="1.3" id="source-independence"><span class="secno">1.3. </span><span class="content">
Source-Order Independence</span><a class="self-link" href="#source-independence"></a></h3>
<figure class="sidefigure">
<img alt="Image: An arrangement suitable for portrait orientation." src="images/game-portrait.png">
<figcaption>An arrangement suitable for “portrait” orientation.</figcaption>
</figure>
<figure class="sidefigure">
<img alt="Image: An arrangement suitable for landscape orientation." src="images/game-landscape.png">
<figcaption>An arrangement suitable for “landscape“ orientation.</figcaption>
</figure>
<p>Continuing the prior example,
the author also wants the game to adapt to the space available on traditional computer monitors, handheld devices, or tablet computers.
Also, the game should optimize the placement of the components when viewed either in portrait or landscape orientation (Figures 4 and 5).
By combining grid layout with media queries,
the author is able to use the same semantic markup,
but rearrange the layout of elements independent of their source order,
to achieve the desired layout in both orientations.</p>
<p>The following example leverages grid layout’s ability to name the space which will be occupied by a <a data-link-type="dfn" href="#grid-item">grid item</a>.
This allows the author to avoid rewriting rules for <a data-link-type="dfn" href="#grid-item">grid items</a>
as the grid’s definition changes.</p>
<div class="example" id="example-c1aac7f6"><a class="self-link" href="#example-c1aac7f6"></a>
<pre class="lang-css highlight" highlight="css"><span class="k">@media</span> <span class="o">(</span><span class="nt">orientation</span><span class="o">:</span> <span class="nt">portrait</span><span class="o">)</span> <span class="p">{</span>
<span class="nf">#grid</span> <span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="n">grid</span><span class="p">;</span>
<span class="c">/* The rows, columns and areas of the grid are defined visually</span>
<span class="c"> * using the grid-template-areas property. Each string is a row,</span>
<span class="c"> * and each word an area. The number of words in a string</span>
<span class="c"> * determines the number of columns. Note the number of words</span>
<span class="c"> * in each string must be identical. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">areas</span><span class="o">:</span> <span class="s2">"title stats"</span>
<span class="s2">"score stats"</span>
<span class="s2">"board board"</span>
<span class="s2">"ctrls ctrls"</span><span class="p">;</span>
<span class="c">/* Columns and rows created with the template property can be</span>
<span class="c"> * assigned a sizing function with the grid-template-columns</span>
<span class="c"> * and grid-template-rows properties. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">columns</span><span class="o">:</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">);</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">rows</span><span class="o">:</span> <span class="k">auto</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">)</span> <span class="k">auto</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="k">@media</span> <span class="o">(</span><span class="nt">orientation</span><span class="o">:</span> <span class="nt">landscape</span><span class="o">)</span> <span class="p">{</span>
<span class="nf">#grid</span> <span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="n">grid</span><span class="p">;</span>
<span class="c">/* Again the template property defines areas of the same name,</span>
<span class="c"> * but this time positioned differently to better suit a</span>
<span class="c"> * landscape orientation. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">areas</span><span class="o">:</span> <span class="s2">"title board"</span>
<span class="s2">"stats board"</span>
<span class="s2">"score ctrls"</span><span class="p">;</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">columns</span><span class="o">:</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">);</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">rows</span><span class="o">:</span> <span class="k">auto</span> <span class="n">minmax</span><span class="p">(</span><span class="n">min</span><span class="o">-</span><span class="k">content</span><span class="o">,</span> <span class="m">1</span><span class="n">fr</span><span class="p">)</span> <span class="k">auto</span>
<span class="p">}</span>
<span class="p">}</span>
<span class="c">/* The grid-area property places a grid item into a named</span>
<span class="c">* region (area) of the grid. */</span>
<span class="nf">#title</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">area</span><span class="o">:</span> <span class="n">title</span> <span class="p">}</span>
<span class="nf">#score</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">area</span><span class="o">:</span> <span class="n">score</span> <span class="p">}</span>
<span class="nf">#stats</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">area</span><span class="o">:</span> <span class="n">stats</span> <span class="p">}</span>
<span class="nf">#board</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">area</span><span class="o">:</span> <span class="n">board</span> <span class="p">}</span>
<span class="nf">#controls</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">area</span><span class="o">:</span> <span class="n">ctrls</span> <span class="p">}</span></pre>
<pre class="lang-markup highlight" highlight="markup"><span class="nt"><div</span> <span class="na">id=</span><span class="s">"grid"</span><span class="nt">></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"title"</span><span class="nt">></span>Game Title<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"score"</span><span class="nt">></span>Score<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"stats"</span><span class="nt">></span>Stats<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"board"</span><span class="nt">></span>Board<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"controls"</span><span class="nt">></span>Controls<span class="nt"></div></span>
<span class="nt"></div></span></pre>
</div>
<h3 class="heading settled" data-level="1.4" id="grid-layering"><span class="secno">1.4. </span><span class="content">
Grid Layering of Elements</span><a class="self-link" href="#grid-layering"></a></h3>
<figure class="sidefigure">
<img alt="Image: A control composed of layered HTML elements." src="images/control-layering-and-alignment.png">
<figcaption>A control composed of layered HTML elements.</figcaption>
</figure>
<p>In the example shown in Figure 6,
the author is creating a custom slider control.
The control has six parts.
The lower and upper labels align to the left and right edges of the control.
The track of the slider spans the area between the labels.
The lower and upper fill parts touch beneath the thumb,
and the thumb is a fixed width and height that can be moved along the track
by updating the two flex-sized columns.</p>
<p>Prior to the introduction of grid layout,
the author would have likely used absolute positioning to control the top and left coordinates,
along with the width and height of each HTML element that comprises the control.
By leveraging grid layout,
the author can instead limit script usage to handling mouse events on the thumb,
which snaps to various positions along the track
as the <a class="property" data-link-type="propdesc" href="#propdef-grid-template-columns">grid-template-columns</a> property of the <a data-link-type="dfn" href="#grid-container">grid container</a> is updated.</p>
<div class="example" id="example-07f44438"><a class="self-link" href="#example-07f44438"></a>
<pre class="lang-css highlight" highlight="css"><span class="nf">#grid</span> <span class="p">{</span>
<span class="k">display</span><span class="o">:</span> <span class="n">grid</span><span class="p">;</span>
<span class="c">/* The grid-template-columns and rows properties also support</span>
<span class="c"> * naming grid lines which can then be used to position grid</span>
<span class="c"> * items. The line names are assigned on either side of a column</span>
<span class="c"> * or row sizing function where the line would logically exist. */</span>
<span class="n">grid</span><span class="o">-</span><span class="n">template</span><span class="o">-</span><span class="n">columns</span><span class="o">:</span>
<span class="p">[</span><span class="n">start</span><span class="p">]</span> <span class="k">auto</span>
<span class="p">[</span><span class="n">track</span><span class="o">-</span><span class="n">start</span><span class="p">]</span> <span class="m">0</span><span class="o">.</span><span class="m">5</span><span class="n">fr</span>
<span class="p">[</span><span class="n">thumb</span><span class="o">-</span><span class="n">start</span><span class="p">]</span> <span class="k">auto</span>
<span class="p">[</span><span class="n">fill</span><span class="o">-</span><span class="n">split</span><span class="p">]</span> <span class="k">auto</span>
<span class="p">[</span><span class="n">thumb</span><span class="o">-</span><span class="n">end</span><span class="p">]</span> <span class="m">0</span><span class="o">.</span><span class="m">5</span><span class="n">fr</span>
<span class="p">[</span><span class="n">track</span><span class="o">-</span><span class="n">end</span><span class="p">]</span> <span class="k">auto</span>
<span class="p">[</span><span class="n">end</span><span class="p">];</span>
<span class="p">}</span>
<span class="c">/* The grid-placement properties accept named lines. Below the</span>
<span class="c">* lines are referred to by name. Beyond any</span>
<span class="c">* semantic advantage, the names also allow the author to avoid</span>
<span class="c">* renumbering the grid-column-start and grid-row-start properties of the</span>
<span class="c">* grid items. This is similar to the concept demonstrated in the</span>
<span class="c">* prior example with the grid-template-areas property during orientation</span>
<span class="c">* changes, but grid lines can also work with layered grid items</span>
<span class="c">* that have overlapping areas of different shapes like the thumb</span>
<span class="c">* and track parts in this example. */</span>
<span class="nf">#lower-label</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">-</span><span class="n">start</span><span class="o">:</span> <span class="n">start</span> <span class="p">}</span>
<span class="nf">#track</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="n">track</span><span class="o">-</span><span class="n">start</span> <span class="o">/</span> <span class="n">track</span><span class="o">-</span><span class="n">end</span><span class="p">;</span> <span class="k">justify</span><span class="o">-</span><span class="n">self</span><span class="o">:</span> <span class="k">center</span> <span class="p">}</span>
<span class="nf">#upper-label</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">-</span><span class="n">end</span><span class="o">:</span> <span class="n">end</span><span class="p">;</span> <span class="p">}</span>
<span class="c">/* Fill parts are drawn above the track so set z-index to 5. */</span>
<span class="nf">#lower-fill</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="n">track</span><span class="o">-</span><span class="n">start</span> <span class="o">/</span> <span class="n">fill</span><span class="o">-</span><span class="n">split</span><span class="p">;</span>
<span class="k">justify</span><span class="o">-</span><span class="n">self</span><span class="o">:</span> <span class="n">end</span><span class="p">;</span>
<span class="k">z-index</span><span class="o">:</span> <span class="m">5</span> <span class="p">}</span>
<span class="nf">#upper-fill</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="n">fill</span><span class="o">-</span><span class="n">split</span> <span class="o">/</span> <span class="n">track</span><span class="o">-</span><span class="n">end</span><span class="p">;</span>
<span class="k">justify</span><span class="o">-</span><span class="n">self</span><span class="o">:</span> <span class="n">start</span><span class="p">;</span>
<span class="k">z-index</span><span class="o">:</span> <span class="m">5</span> <span class="p">}</span>
<span class="c">/* Thumb is the topmost part; assign it the highest z-index value. */</span>
<span class="nf">#thumb</span> <span class="p">{</span> <span class="n">grid</span><span class="o">-</span><span class="n">column</span><span class="o">:</span> <span class="n">thumb</span><span class="o">-</span><span class="n">start</span> <span class="o">/</span> <span class="n">thumb</span><span class="o">-</span><span class="n">end</span><span class="p">;</span> <span class="k">z-index</span><span class="o">:</span> <span class="m">10</span> <span class="p">}</span></pre>
<pre class="lang-markup highlight" highlight="markup"><span class="nt"><div</span> <span class="na">id=</span><span class="s">"grid"</span><span class="nt">></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"lower-label"</span><span class="nt">></span>Lower Label<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"upper-label"</span><span class="nt">></span>Upper Label<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"track"</span><span class="nt">></span>Track<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"lower-fill"</span><span class="nt">></span>Lower Fill<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"upper-fill"</span><span class="nt">></span>Upper Fill<span class="nt"></div></span>
<span class="nt"><div</span> <span class="na">id=</span><span class="s">"thumb"</span><span class="nt">></span>Thumb<span class="nt"></div></span>
<span class="nt"></div></span></pre>
</div>
<h2 class="heading settled" data-level="2" id="grid-concepts"><span class="secno">2. </span><span class="content">
Grid Layout Concepts and Terminology</span><a class="self-link" href="#grid-concepts"></a></h2>
<p>In <dfn data-dfn-type="dfn" data-export="" id="grid-layout">grid layout<a class="self-link" href="#grid-layout"></a></dfn>,
the content of a <a data-link-type="dfn" href="#grid-container">grid container</a> is laid out
by positioning and aligning it into a <a data-link-type="dfn" href="#grid">grid</a>.
The <dfn data-dfn-type="dfn" data-export="" id="grid">grid<a class="self-link" href="#grid"></a></dfn> is an intersecting set of horizontal and vertical <a data-link-type="dfn" href="#grid-line">grid lines</a>
that divides the <a data-link-type="dfn" href="#grid-container">grid container</a>’s space into <a data-link-type="dfn" href="#grid-area">grid areas</a>,
into which <a data-link-type="dfn" href="#grid-item">grid items</a> (representing the <a data-link-type="dfn" href="#grid-container">grid container</a>’s content) can be placed.
There are two sets of <a data-link-type="dfn" href="#grid-line">grid lines</a>:
one set defining <dfn data-dfn-type="dfn" data-export="" data-lt="grid column | column" id="grid-column">columns<a class="self-link" href="#grid-column"></a></dfn>
that run along the <a href="http://www.w3.org/TR/css3-writing-modes/#block-axis-">block axis</a> (the <dfn data-dfn-type="dfn" data-export="" id="column-axis">column axis<a class="self-link" href="#column-axis"></a></dfn>),
and an orthogonal set defining <dfn data-dfn-type="dfn" data-export="" data-lt="grid row | row" id="grid-row">rows<a class="self-link" href="#grid-row"></a></dfn>
along the <a href="http://www.w3.org/TR/css3-writing-modes/#inline-axis-">inline axis</a> (the <dfn data-dfn-type="dfn" data-export="" id="row-axis">row axis<a class="self-link" href="#row-axis"></a></dfn>).
<a data-link-type="biblio" href="#biblio-css3-writing-modes">[CSS3-WRITING-MODES]</a></p>
<figure>
<img alt="Image: Grid Lines." class="figure" src="images/grid-lines.png">
<figcaption>Grid lines: Three in the block axis and four in the inline axis.</figcaption>
</figure>
<h3 class="heading settled" data-level="2.1" id="grid-track-concept"><span class="secno">2.1. </span><span class="content">
Grid Tracks and Cells</span><a class="self-link" href="#grid-track-concept"></a></h3>
<p><dfn data-dfn-type="dfn" data-export="" id="grid-track">Grid track<a class="self-link" href="#grid-track"></a></dfn> is a generic term for a <a data-link-type="dfn" href="#grid-column">grid column</a> or <a data-link-type="dfn" href="#grid-row">grid row</a>—in
other words, it is the space between two adjacent <a data-link-type="dfn" href="#grid-line">grid lines</a>.
Each <a data-link-type="dfn" href="#grid-track">grid track</a> is assigned a sizing function,
which controls how wide or tall the column or row may grow,
and thus how far apart its bounding <a data-link-type="dfn" href="#grid-line">grid lines</a> are.</p>
<p>A <dfn data-dfn-type="dfn" data-export="" id="grid-cell">grid cell<a class="self-link" href="#grid-cell"></a></dfn> is the similar term for the full grid—it
is the space between two adjacent row and two adjacent column <a data-link-type="dfn" href="#grid-line">grid lines</a>.
It is the smallest unit of the grid that can be referenced when positioning <a data-link-type="dfn" href="#grid-item">grid items</a>.</p>
<div class="example" id="example-35388f26"><a class="self-link" href="#example-35388f26"></a>
In the following example there are two columns and three rows.
The first column is fixed at 150px.
The second column uses flexible sizing, which is a function of the unassigned space in the Grid,
and thus will vary as the width of the <a data-link-type="dfn" href="#grid-container">grid container</a> changes.
If the used width of the <a data-link-type="dfn" href="#grid-container">grid container</a> is 200px, then the second column 50px wide.
If the used width of the <a data-link-type="dfn" href="#grid-container">grid container</a> is 100px, then the second column is 0px
and any content positioned in the column will overflow the <a data-link-type="dfn" href="#grid-container">grid container</a>.
<pre><style type="text/css">
#grid {
display: grid;
grid-template-columns: 150px 1fr; /* two columns */
grid-template-rows: 50px 1fr 50px /* three rows */
}
</style>
</pre>
</div>
<h3 class="heading settled" data-level="2.2" id="grid-line-concept"><span class="secno">2.2. </span><span class="content">
Grid Lines</span><a class="self-link" href="#grid-line-concept"></a></h3>
<p><dfn data-dfn-type="dfn" data-export="" data-lt="grid line|grid row line|grid column line" id="grid-line">Grid lines<a class="self-link" href="#grid-line"></a></dfn> are the horizontal and vertical dividing lines of the <a data-link-type="dfn" href="#grid">grid</a>.
A <a data-link-type="dfn" href="#grid-line">grid line</a> exists on either side of a column or row.
They can be referred to by numerical index,
or by an author-specified name.
A <a data-link-type="dfn" href="#grid-item">grid item</a> references the <a data-link-type="dfn" href="#grid-line">grid lines</a> to determine its position within the <a data-link-type="dfn" href="#grid">grid</a>
using the <a href="#placement">grid-placement properties</a>.</p>
<div class="example" id="example-07ee9d6e"><a class="self-link" href="#example-07ee9d6e"></a>
The following two examples create three column <a data-link-type="dfn" href="#grid-line">grid lines</a> and four row <a data-link-type="dfn" href="#grid-line">grid lines</a>.
The first example demonstrates how an author would position a <a data-link-type="dfn" href="#grid-item">grid item</a> using <a data-link-type="dfn" href="#grid-line">grid line</a> numbers.
The second example uses explicitly named <a data-link-type="dfn" href="#grid-line">grid lines</a>.
<pre><style type="text/css">
#grid {
display: grid;
grid-template-columns: 150px 1fr;
grid-template-rows: 50px 1fr 50px
}
#item1 { grid-column: 2;
grid-row-start: 1; grid-row-end: 4; }
</style>
</pre>
<pre><style type="text/css">
/* equivalent layout to the prior example, but using named lines */
#grid {
display: grid;
grid-template-columns: 150px [item1-start] 1fr [item1-end];
grid-template-rows: [item1-start] 50px 1fr 50px [item1-end];
}
#item1 {
grid-column: item1-start / item1-end;
grid-row: item1-start / item1-end
}
</style>
</pre>
</div>
<h3 class="heading settled" data-level="2.3" id="grid-area-concept"><span class="secno">2.3. </span><span class="content">
Grid Areas</span><a class="self-link" href="#grid-area-concept"></a></h3>
<p>A <dfn data-dfn-type="dfn" data-export="" id="grid-area">grid area<a class="self-link" href="#grid-area"></a></dfn> is the logical space used to lay out one or more <a data-link-type="dfn" href="#grid-item">grid items</a>.
It is bound by four <a data-link-type="dfn" href="#grid-line">grid lines</a>, one on each side of the <a data-link-type="dfn" href="#grid-area">grid area</a>,
and participates in the sizing of the <a data-link-type="dfn" href="#grid-track">grid tracks</a> it intersects.
A <a data-link-type="dfn" href="#grid-area">grid area</a> can be named explicitly using the <a class="property" data-link-type="propdesc" href="#propdef-grid-template-areas">grid-template-areas</a> property of the <a data-link-type="dfn" href="#grid-container">grid container</a>,
or referenced implicitly by its bounding <a data-link-type="dfn" href="#grid-line">grid lines</a>.
A <a data-link-type="dfn" href="#grid-item">grid item</a> is assigned to a <a data-link-type="dfn" href="#grid-area">grid area</a>
using the <a href="#placement">grid-placement properties</a>.</p>
<div class="example" id="example-05759431"><a class="self-link" href="#example-05759431"></a>
<pre><style type="text/css">
/* using the template syntax */
#grid {
display: grid;
grid-template-areas: ". a"
"b a"
". a";
grid-template-columns: 150px 1fr;
grid-template-rows: 50px 1fr 50px
}
#item1 { grid-area: a }
#item2 { grid-area: b }
#item3 { grid-area: b }
/* Align items 2 and 3 at different points in the Grid Area "b". */
/* By default, Grid Items are stretched to fit their Grid Area */
/* and these items would layer one over the other. */
#item2 { align-self: start }
#item3 { justify-self: end; align-self: end }
</style>
</pre>
</div>
<p>A <a data-link-type="dfn" href="#grid-item">grid item</a>’s <a data-link-type="dfn" href="#grid-area">grid area</a> forms the containing block into which it is laid out.
Percentage lengths specified on a <a data-link-type="dfn" href="#grid-item">grid item</a> resolve against this containing block.
Percentages specified for <a class="property" data-link-type="propdesc" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-top">margin-top</a>, <a class="property" data-link-type="propdesc" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-top">padding-top</a>, <a class="property" data-link-type="propdesc" href="http://www.w3.org/TR/CSS21/box.html#propdef-margin-bottom">margin-bottom</a>, and <a class="property" data-link-type="propdesc" href="http://www.w3.org/TR/CSS21/box.html#propdef-padding-bottom">padding-bottom</a> on a <a data-link-type="dfn" href="#grid-item">grid item</a>
resolve against the height of its containing block,
rather than the width (as for blocks).</p>
<p class="issue" id="issue-2cf2761e"><a class="self-link" href="#issue-2cf2761e"></a> This margin/padding behavior is disputed.
<a href="https://lists.w3.org/Archives/Public/www-style/2015Mar/0273.html">(see discussion)</a></p>
<p><a data-link-type="dfn" href="#grid-item">Grid items</a> placed into the same <a data-link-type="dfn" href="#grid-area">grid area</a> do not directly affect each other’s layout.
Indirectly, a <a data-link-type="dfn" href="#grid-item">grid item</a> can affect the position of a <a data-link-type="dfn" href="#grid-line">grid line</a> in a column or row that uses a content-based relative size,
which in turn can affect the position or size of another <a data-link-type="dfn" href="#grid-item">grid item</a>.</p>