border-block-start-color

This is an experimental technology
Check the Browser compatibility table carefully before using this in production.

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

border-block-start-color: blue;
border-block-start-color: #4c5d21;

Related properties are border-block-end-colorborder-inline-start-color, and border-inline-end-color, which define the other border colors of the element.

Initial valuecurrentcolor
Applies toall elements
Inheritedno
Mediavisual
Computed valuecomputed color
Animation typediscrete
Canonical orderthe unique non-ambiguous order defined by the formal grammar

Syntax

Values

<'color'>
See border-color

Formal syntax

<'color'>

where
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>

where
<rgb()> = rgb( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<rgba()> = rgba( [ [ <percentage>{3} | <number>{3} ] [ / <alpha-value> ]? ] | [ [ <percentage>#{3} | <number>#{3} ] , <alpha-value>? ] )
<hsl()> = hsl( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )
<hsla()> = hsla( [ <hue> <percentage> <percentage> [ / <alpha-value> ]? ] | [ <hue>, <percentage>, <percentage>, <alpha-value>? ] )

where
<alpha-value> = <number> | <percentage>
<hue> = <number> | <angle>

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;
  border: 10px solid blue;
  border-block-start-color: red;
}

Specification

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

Browser compatibility

FeatureChromeEdgeFirefoxInternet ExplorerOperaSafari
Basic support No ?

41

38 — 511

No No No
FeatureAndroid webviewChrome for AndroidEdge mobileFirefox for AndroidIE mobileOpera AndroidiOS Safari
Basic support No ? ?

41

38 — 511

No No No

1. From version 38 until version 51 (exclusive): this feature is behind the layout.css.vertical-text.enabled preference (needs to be set to true). To change preferences in Firefox, visit about:config.

See also

Document Tags and Contributors

 Contributors to this page: ddbeck, mfluehr, elysdir1, teoli, Sebastianz, fscholz, jsx, kscarfone
 Last updated by: ddbeck,