inset-inline-start

Baseline Widely available *

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

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

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

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

Try it

writing-mode: horizontal-tb;

writing-mode: vertical-rl;

writing-mode: horizontal-tb;
direction: rtl;

writing-mode: vertical-lr;

<section id="default-example">
  <div class="example-container" id="example-element">
    <div id="abspos">
      I am absolutely positioned with inset-inline-start: 50px
    </div>
    <p>
      As much mud in the streets as if the waters had but newly retired from the
      face of the earth, and it would not be wonderful to meet a Megalosaurus,
      forty feet long or so, waddling like an elephantine lizard up Holborn
      Hill.
    </p>
  </div>
</section>

#example-element {
  border: 0.75em solid;
  padding: 0.75em;
  position: relative;
  width: 100%;
  min-height: 200px;
  unicode-bidi: bidi-override;
}

#abspos {
  background-color: yellow;
  color: black;
  border: 3px solid red;
  position: absolute;
  inset-inline-start: 50px;
  inline-size: 140px;
  min-block-size: 80px;
}

Syntax

/* <length> values */
inset-inline-start: 3px;
inset-inline-start: 2.4em;
inset-inline-start: calc(anchor(--myAnchor 50%) + 10px);
inset-inline-start: anchor-size(width);

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

/* Keyword value */
inset-inline-start: auto;

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

The shorthand for inset-inline-start and inset-inline-end is inset-inline.

Values

The inset-inline-start property takes the same values as the left property.

Formal definition

Initial value	`auto`
Applies to	positioned elements
Inherited	no
Percentages	logical-width of containing block
Computed value	same as box offsets: `top`, `right`, `bottom`, `left` properties except that directions are logical
Animation type	a length, percentage or calc();

Formal syntax

inset-inline-start = 
  auto                 |
  <length-percentage>  

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

Examples

Setting inline start offset

HTML

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

CSS

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

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

Result

Specifications

Specification
CSS Logical Properties and Values Level 1 # propdef-inset-inline-start
CSS Positioned Layout Module Level 3 # propdef-inset-inline-start

Browser compatibility

	Desktop					Mobile
	Chrome	Edge	Firefox	Opera	Safari	Chrome Android	Firefox for Android	Opera Android	Safari on IOS	Samsung Internet	WebView Android
`inset-inline-start`	87	87	6341–63	73	14.1	87	6341–63	62	14.5	14.0	87
`anchor`	125	125	No	111	No	125	No	83	No	27.0	125
`anchor-size`	132	132	No	117	No	132	No	87	No	No	132
`auto`	87	87	41	73	14.1	87	41	62	14.5	14.0	87