The CSS align-items
property defines how the browser distributes space between and around flex items along the cross-axis of their container. This means it works like justify-content
but in the perpendicular direction.
/* Basic keywords */ align-items: normal; align-items: stretch; /* Positional alignment */ align-items: center; /* Pack items around the center */ align-items: start; /* Pack items from the start */ align-items: end; /* Pack items from the end */ align-items: flex-start; /* Pack flex items from the start */ align-items: flex-end; /* Pack flex items from the end */ align-items: self-start; align-items: self-end; align-items: left; /* Pack items from the left */ align-items: right; /* Pack items from the right */ /* Baseline alignment */ align-items: baseline; align-items: first baseline; align-items: last baseline; /* Overflow alignment (for positional alignment only) */ align-items: safe center; align-items: unsafe center; /* Global values */ align-items: inherit; align-items: initial; align-items: unset;
The difference to the align-content
property is that align-items
specifies the alignment of the items within the current flex container's line, whereas align-content
specifies the alignment of the lines themselves.
<div class="grid"> <div class="col"> <div class="row"> <div class="cell"> normal <div class="container normal"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> stretch <div class="container stretch"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> center <div class="container center"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> baseline <div class="container baseline"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> start <div class="container start"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> flex-start <div class="container flex-start"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> self-start <div class="container self-start"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> left <div class="container left"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> end <div class="container end"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> flex-end <div class="container flex-end"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> self-end <div class="container self-end"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> right <div class="container right"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> first baseline <div class="container first-baseline"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> last baseline <div class="container last-baseline"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> safe center <div class="container safe-center"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> <div class="cell"> unsafe center <div class="container unsafe-center"> <div class="item A">A</div> <div class="item B">B</div> <div class="item C">C</div> </div> </div> </div> <div class="note"> The exact behavior of the align-items property is highly bound to some other properties: <div class="row"> <div class="code flex"> <code>.container {</code> <code> align-items: /* See above */;</code> <code> display:<select id="display"><option>flex</option><option>grid</option></select>;</code> <code class="flex"> flex-direction:<select id="flexDirection"><option>row</option><option>row-reverse</option><option>column</option><option>column-reverse</option></select>;</code> <code class="flex"> direction:<select id="direction"><option>ltr</option><option>rtl</option></select>;</code> <code class="grd" > grid-template-columns: repeat(auto-fill, 33%);</code> <code>}</code> </div> <div class="code"> <code>.item {</code> <code> width: <select id="width"><option>auto</option><option>2em</option></select></code> <code> height: <select id="height"><option>auto</option><option>2em</option></select></code> <code> position: <select id="position"><option>static</option><option>absolute</option></select></code> <code>}</code> </div> </div> </div> </div> </div>
html,body { height: 100%; box-sizing: border-box; } .grid { width: 100%; height: 100%; display: flex; background: #EEE; font: 1em monospace; } .row { display: flex; flex: 1 auto; flex-direction: row; flex-wrap: wrap; justify-content: space-between; align-content: start; } .col { display: flex; flex: 1 auto; flex-direction: column; } .cell { margin: .5em; padding: .5em; background-color: #FFF; overflow: hidden; text-align: center; width: 10.5em; } .note { background: #fff3d4; padding: 1em; margin: .5em; font: .8em sans-serif; text-align: left; flex: none; } .note .row { justify-content: flex-start; margin-top: .5rem; } .code { margin-right: 1em; line-height: 2.5; } code { display: block; } .container { display: flex; background: #000; width: 10.5em; height: 10.5em; max-width: 10.5em; max-height: 10.5em; grid-template-columns: repeat(auto-fill, 33%); overflow: hidden; resize: both; } .item { background: #E4F0F5; box-sizing: border-box; padding: .5em; margin: 1px; } .A { font-size: .8rem; } .B { font-size: 1.8rem; } .C { font-size: 1.3rem; } .normal { align-items: normal; } .stretch { align-items: stretch; } .center { align-items: center; } .start { align-items: start; } .end { align-items: end; } .flex-start { align-items: flex-start; } .flex-end { align-items: flex-end; } .self-start { align-items: self-start; } .self-end { align-items: self-end; } .left { align-items: left; } .right { align-items: right; } .baseline { align-items: baseline; } .first-baseline { align-items: first baseline; } .last-baseline { align-items: last baseline; } .safe-center { align-items: safe center; } .unsafe-center { align-items: unsafe center; }
window.addEventListener('load', function () { var select = Array.from(document.querySelectorAll('select')); var container = Array.from(document.querySelectorAll('.container')); var item = Array.from(document.querySelectorAll('.item')); function getData() { return select.reduce(function (obj, field) { obj[field.id] = field.value return obj }, {}); } window.addEventListener('input', function () { var data = getData(); container.forEach(function (c) { c.style.display = data.display; c.style.direction = data.direction; c.style.flexDirection = data.flexDirection; }) item.forEach(function (c) { c.style.width = data.width; c.style.height = data.height; c.style.position = data.position; }) }); })
Initial value | stretch |
---|---|
Applies to | flex containers |
Inherited | no |
Media | visual |
Computed value | as specified |
Animation type | discrete |
Canonical order | the unique non-ambiguous order defined by the formal grammar |
Syntax
Values
normal
- The effect of this keyword is dependent of the layout mode we are in:
- In absolutely-positioned layouts, the keyword behaves like
start
on replaced absolutely-positioned boxes, and asstretch
on all other absolutely-positioned boxes. - In static position of absolutely-positioned layouts, the keyword behaves as
stretch
. - For flex items, the keyword behaves as
stretch
. - For grid items, this keyword leads to a behavior similar to the one of
stretch
, except for boxes with an aspect ratio or an intrinsic sizes where it behaves likestart
. - The property doesn't apply to block-level boxes, and to table cells.
- In absolutely-positioned layouts, the keyword behaves like
flex-start
- The cross-start margin edge of the flex item is flushed with the cross-start edge of the line.
flex-end
- The cross-end margin edge of the flex item is flushed with the cross-end edge of the line.
center
- The flex item's margin box is centered within the line on the cross-axis. If the cross-size of the item is larger than the flex container, it will overflow equally in both directions.
start
- The item is packed flush to each other toward the start edge of the alignment container in the appropriate axis.
end
- The item is packed flush to each other toward the end edge of the alignment container in the appropriate axis.
center
- The items are packed flush to each other toward the center of the of the alignment container.
left
- The items are packed flush to each other toward the left edge of the alignment container. If the property’s axis is not parallel with the inline axis, this value behaves like
start
. right
- The items are packed flush to each other toward the right edge of the alignment container in the appropriate axis. If the property’s axis is not parallel with the inline axis, this value behaves like
start
. self-start
- The items is packed flush to the edge of the alignment container of the start side of the item, in the appropriate axis.
self-end
- The item is packed flush to the edge of the alignment container of the end side of the item, in the appropriate axis.
baseline
first baseline
last baseline- All flex items are aligned such that their baselines align. The item with the largest distance between its cross-start margin edge and its baseline is flushed with the cross-start edge of the line.
stretch
- Flex items are stretched such as the cross-size of the item's margin box is the same as the line while respecting width and height constraints.
safe
- If the size of the item overflows the alignment container, the item is instead aligned as if the alignment mode were
start
. unsafe
- Regardless of the relative sizes of the item and alignment container, the given alignment value is honored.
-
Formal syntax
flex-start | flex-end | center | baseline | stretch
Example
CSS
#container { height:200px; width: 240px; align-items: center; /* Can be changed in the live sample */ background-color: #8c8c8c; } .flex { display: flex; flex-wrap: wrap; } .grid { display: grid; grid-template-columns: repeat(auto-fill, 50px); } div > div { box-sizing: border-box; border: 2px solid #8c8c8c; width: 50px; display: flex; align-items: center; justify-content: center; } #item1 { background-color: #8cffa0; min-height: 30px; } #item2 { background-color: #a0c8ff; min-height: 50px; } #item3 { background-color: #ffa08c; min-height: 40px; } #item4 { background-color: #ffff8c; min-height: 60px; } #item5 { background-color: #ff8cff; min-height: 70px; } #item6 { background-color: #8cffff; min-height: 50px; font-size: 30px; } select { font-size: 16px; } .row { margin-top: 10px; }
HTML
<div id="container" class="flex"> <div id="item1">1</div> <div id="item2">2</div> <div id="item3">3</div> <div id="item4">4</div> <div id="item5">5</div> <div id="item6">6</div> </div> <div class="row"> <label for="display">display: </label> <select id="display"> <option value="flex">flex</option> <option value="grid">grid</option> </select> </div> <div class="row"> <label for="values">align-items: </label> <select id="values"> <option value="normal">normal</option> <option value="flex-start">flex-start</option> <option value="flex-end">flex-end</option> <option value="center" selected>center</option> <option value="baseline">baseline</option> <option value="stretch">stretch</option> <option value="start">start</option> <option value="end">end</option> <option value="self-start">self-start</option> <option value="self-end">self-end</option> <option value="left">left</option> <option value="right">right</option> <option value="first baseline">first baseline</option> <option value="last baseline">last baseline</option> <option value="safe center">safe center</option> <option value="unsafe center">unsafe center</option> <option value="safe right">safe right</option> <option value="unsafe right">unsafe right</option> <option value="safe end">safe end</option> <option value="unsafe end">unsafe end</option> <option value="safe self-end">safe self-end</option> <option value="unsafe self-end">unsafe self-end</option> <option value="safe flex-end">safe flex-end</option> <option value="unsafe flex-end">unsafe flex-end</option> </select> </div>
JavaScript
var values = document.getElementById('values'); var display = document.getElementById('display'); var container = document.getElementById('container'); values.addEventListener('change', function (evt) { container.style.alignItems = evt.target.value; }); display.addEventListener('change', function (evt) { container.className = evt.target.value; });
Result
Specifications
Specification | Status | Comment |
---|---|---|
CSS Box Alignment Module Level 3 The definition of 'align-items' in that specification. |
Working Draft | Adds the [ first | last ]? baseline , self-start , self-end , start , end , left , right , unsafe | safe values. |
CSS Flexible Box Layout Module The definition of 'align-items' in that specification. |
Candidate Recommendation | Initial definition |
Browser compatibility
Feature | Chrome | Edge | Firefox | Internet Explorer | Opera | Safari |
---|---|---|---|---|---|---|
Basic support | 211 | Yes Yes -webkit- | 202 49 -webkit- 18 —?3 | 115 | 12.1 | 7 -webkit- |
first baseline and last baseline | ? | ? | 45 | ? | ? | ? |
start and end | ? | ? | 45 | ? | ? | ? |
left and right | ? | ? | 45 | ? | ? | ? |
Feature | Android webview | Chrome for Android | Edge mobile | Firefox for Android | IE mobile | Opera Android | iOS Safari |
---|---|---|---|---|---|---|---|
Basic support | 4.4 | ? | Yes Yes -webkit- | 202 49 -webkit- 18 —?3 | No | 12.1 | 7 -webkit- |
first baseline and last baseline | ? | ? | ? | 45 | ? | ? | ? |
start and end | ? | ? | ? | 45 | ? | ? | ? |
left and right | ? | ? | ? | 45 | ? | ? | ? |
1. Older versions of the specification treat absolute positioned children as though they are a 0 by 0 flex item. Later specification versions take the children out of the flow and set their positions based on align and justify properties. Chrome implements the new behavior beginning with Chrome 52.
2. Multi-line flexbox has been supported since Firefox 28.
3. From version 18: this feature is behind the layout.css.flexbox.enabled
preference (needs to be set to true
). To change preferences in Firefox, visit about:config.
4. From version 48: this feature is behind the layout.css.prefixes.webkit
preference (needs to be set to true
). To change preferences in Firefox, visit about:config.
5. In Internet Explorer 10 and 11, if column flex items have align-items: center;
set on them and their content is too large, then they will overflow the bounds of their container. See Flexbug #2.
See also
- CSS Flexbox Guide: Basic Concepts of Flexbox
- CSS Flexbox Guide: Aligning items in a flex container