The flex
CSS shorthand property sets how a flex item will grow or shrink to fit the space available in its flex container.
This property is a shorthand for the following CSS properties:
/* Keyword values */ flex: auto; flex: initial; flex: none; /* One value, unitless number: flex-grow */ flex: 2; /* One value, width/height: flex-basis */ flex: 10em; flex: 30%; flex: min-content; /* Two values: flex-grow | flex-basis */ flex: 1 30px; /* Two values: flex-grow | flex-shrink */ flex: 2 2; /* Three values: flex-grow | flex-shrink | flex-basis */ flex: 2 2 10%; /* Global values */ flex: inherit; flex: initial; flex: unset;
The flex
property may be specified using one, two, or three values.
<number>
: In this case it is interpreted as flex: <number> 1 0
; the <flex-shrink>
value is assumed to be 1 and the <flex-basis>
value is assumed to be 0
.none
, auto
, or initial
.<number>
and it is interpreted as <flex-grow>
.<number>
: then it is interpreted as <flex-shrink>
.width
: then it is interpreted as <flex-basis>
.<number>
for <flex-grow>
.<number>
for <flex-shrink>
.width
for <flex-basis>
.initial
width
and height
properties. It shrinks to its minimum size to fit the container, but does not grow to absorb any extra free space in the flex container. This is equivalent to setting "flex: 0 1 auto
".auto
width
and height
properties, but grows to absorb any extra free space in the flex container, and shrinks to its minimum size to fit the container. This is equivalent to setting "flex: 1 1 auto
".none
width
and height
properties. It is fully inflexible: it neither shrinks nor grows in relation to the flex container. This is equivalent to setting "flex: 0 0 auto
".<'flex-grow'>
flex-grow
of the flex item. Negative values are considered invalid. Defaults to 1
when omitted. (initial is 0
)<'flex-shrink'>
flex-shrink
of the flex item. Negative values are considered invalid. Defaults to 1
when omitted. (initial is 1
)<'flex-basis'>
flex-basis
of the flex item. A preferred size of 0
must have a unit to avoid being interpreted as a flexibility. Defaults to 0
when omitted. (initial is auto
)For most purposes, authors should set flex
to one of the following values: auto
, initial
, none
, or a positive unitless number. To see the effect of these values, try resizing the flex containers below:
By default flex items don't shrink below their minimum content size. To change this, set the item's min-width
or min-height
.
Initial value | as each of the properties of the shorthand:
|
---|---|
Applies to | flex items, including in-flow pseudo-elements |
Inherited | no |
Computed value | as each of the properties of the shorthand:
|
Animation type | as each of the properties of the shorthand:
|
none | [ <'flex-grow'> <'flex-shrink'>? || <'flex-basis'> ]
<div id="flex-container"> <div class="flex-item" id="flex">Flex box (click to toggle raw box)</div> <div class="raw-item" id="raw">Raw box</div> </div>
#flex-container { display: flex; flex-direction: row; } #flex-container > .flex-item { flex: auto; } #flex-container > .raw-item { width: 5rem; }
Specification | Status | Comment |
---|---|---|
CSS Flexible Box Layout Module The definition of 'flex' in that specification. | Candidate Recommendation | Initial definition |
Desktop | ||||||
---|---|---|---|---|---|---|
flex |
29
|
12
|
20
|
11
|
12.1 | 9
|
Mobile | ||||||
---|---|---|---|---|---|---|
flex |
4.4
|
29
|
20
|
12.1 | 9
|
2.0
|
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https://developer.mozilla.org/en-US/docs/Web/CSS/flex