inset-block-start

The inset-block-start CSS property defines the logical block start offset of an element, which maps to a physical inset 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.

/* <length> values */
inset-block-start: 3px;
inset-block-start: 2.4em;

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

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

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

Syntax

Values

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

Formal definition

Initial value auto
Applies to positioned elements
Inherited no
Percentages logical-height 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

<'top'>

Examples

Setting block 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-block-start: 20px;
  background-color: #c8c800;
}

Specifications

Browser compatibility

Desktop Mobile
Chrome Edge Firefox Internet Explorer Opera Safari WebView Android Chrome Android Firefox for Android Opera Android Safari on IOS Samsung Internet
inset-block-start
87
69
87
79
63
41-63
No
73
56
14.1
87
87
69
63
41-63
62
14.5
14.0

See also

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Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/inset-block-start