inset-block

Baseline Widely available *

This feature is well established and works across many devices and browser versions. It’s been available across browsers since September 2021.

* Some parts of this feature may have varying levels of support.

The inset-block CSS property defines the logical block start and end offsets of an element, which maps to physical offsets depending on the element's writing mode, directionality, and text orientation. It corresponds to the top and bottom, or right and left properties depending on the values defined for writing-mode, direction, and text-orientation.

This inset property has no effect on non-positioned elements.

Try it

Constituent properties

This property is a shorthand for the following CSS properties:

Syntax

css
/* <length> values */
inset-block: 3px 10px;
inset-block: 2.4em 3em;
inset-block: 10px; /* value applied to start and end */
inset-block: auto anchor(start);
inset-block: 10em anchor-size(--myAnchor height, 10%);

/* <percentage>s of the width or height of the containing block */
inset-block: 10% 5%;

/* Keyword value */
inset-block: auto;

/* Global values */
inset-block: inherit;
inset-block: initial;
inset-block: revert;
inset-block: revert-layer;
inset-block: unset;

Values

The inset-block property takes the same values as the left property.

Formal definition

Initial valueas each of the properties of the shorthand:
Applies topositioned elements
Inheritedno
Percentageslogical-height of containing block
Computed valueas each of the properties of the shorthand:
Animation typea length, percentage or calc();

Formal syntax

inset-block = 
<'top'>{1,2}

<top> =
auto |
<length-percentage> |
<anchor()> |
<anchor-size()>

<length-percentage> =
<length> |
<percentage>

<anchor()> =
anchor( <anchor-name>? &&
<anchor-side> , <length-percentage>? )

<anchor-size()> =
anchor-size( [ <anchor-name> || <anchor-size> ]? , <length-percentage>? )

<anchor-name> =
<dashed-ident>

<anchor-side> =
inside |
outside |
top |
left |
right |
bottom |
start |
end |
self-start |
self-end |
<percentage> |
center

<anchor-size> =
width |
height |
block |
inline |
self-block |
self-inline

Examples

Setting block start and end offsets

HTML

html
<div>
  <p class="exampleText">Example text</p>
</div>

CSS

css
div {
  background-color: yellow;
  width: 120px;
  height: 120px;
}

.exampleText {
  writing-mode: vertical-lr;
  position: relative;
  inset-block: 20px 50px;
  background-color: #c8c800;
}

Result

Specifications

Specification
CSS Logical Properties and Values Level 1
# propdef-inset-block

Browser compatibility

Report problems with this compatibility data on GitHub
desktopmobile
Chrome
Edge
Firefox
Opera
Safari
Chrome Android
Firefox for Android
Opera Android
Safari on iOS
Samsung Internet
WebView Android
WebView on iOS
inset-block
anchor()
Experimental
anchor-size()
Experimental
auto

Legend

Tip: you can click/tap on a cell for more information.

Full support
Full support
In development. Supported in a pre-release version.
In development. Supported in a pre-release version.
No support
No support
Experimental. Expect behavior to change in the future.
See implementation notes.
Uses a non-standard name.
Has more compatibility info.

See also