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offset-block-start

This is an experimental technology
Because this technology's specification has not stabilized, check the compatibility table for usage in various browsers. Also note that the syntax and behavior of an experimental technology is subject to change in future versions of browsers as the specification changes.

The offset-block-start CSS property defines the logical block start offset 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.

It relates to offset-block-end, offset-inline-start, and offset-inline-end, which define the other offsets of the element.

Initial value auto
Applies to positioned elements
Inherited no
Percentages logical-height of containing block
Media visual
Computed value same as box offsets: top, right, bottom, left properties except that directions are logical
Animation type discrete
Canonical order the unique non-ambiguous order defined by the formal grammar

Syntax

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

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

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

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

Values

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

Formal syntax

<'left'>

Example

HTML Content

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

CSS Content

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

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

Specification

Specification Status Comment
CSS Logical Properties Level 1
The definition of 'offset-block-start' in that specification.
Editor's Draft Initial definition

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support No support 41.0 (41.0)[1] No support No support No support
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support No support 41.0 (41.0)[1] No support No support No support

[1] Available since Gecko 38, but behind the preference layout.css.vertical-text.enabled, then disabled by default. The preference has been removed in Gecko 51 and this property cannot be disabled since this version.

See also

© 2005–2017 Mozilla Developer Network and individual contributors.
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-US/docs/Web/CSS/offset-block-start