CSS - offset-block-start

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.

Example

 

HTML Content

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

CSS Content

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

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

Syntax  

CSS
/* <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

CSS
<a href="css/left" title="&lt;length&gt; | &lt;percentage&gt; | auto"><'left'></a>

Description  

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 valueauto
Applies topositioned elements
Inheritedno
Percentageslogical-height of containing block
Mediavisual
Computed valuesame as box offsets: top, right, bottom, left properties except that directions are logical
Animatableno
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Browser Compatibility  

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support Not supported 41.0 (41.0)[1] Not supported Not supported Not supported
Feature Android Firefox Mobile (Gecko) IE Phone Opera Mobile Safari Mobile
Basic support Not supported 41.0 (41.0)[1] Not supported Not supported Not supported

[1] Available since Gecko 38, but behind the preference layout.css.vertical-text.enabled, then disabled by default.

See Also  

 

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

License

© 2016 Mozilla 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

CSS CSS Logical Property CSS Property Experimental NeedsContent Reference