border-block-start

Summary

The border-block-start CSS property is a shorthand property for setting the individual logical block start border property values in a single place in the style sheet. border-block-start can be used to set the values for one or more of: border-block-start-width, border-block-start-style, border-block-start-color. It maps to a physical border depending on the element's writing mode, directionality, and text orientation. It corresponds to the border-top, border-right, border-bottom, or border-left property depending on the values defined for writing-mode, direction, and text-orientation.

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

Syntax

border-block-start: 1px;
border-block-start: 2px dotted;
border-block-start: medium dashed blue;

Values

One or more of the following, in any order:

<'border-width'>

See border-width

<'border-style'>

See border-style

<'color'>

See color

Formal syntax

<'border-width'> || <'border-style'> || <'color'>
where 
<color> = <rgb()> | <rgba()> | <hsl()> | <hsla()> | <hex-color> | <named-color> | currentcolor | <deprecated-system-color>
where 
<rgb()> = rgb( <rgb-component>#{3} )
<rgba()> = rgba( <rgb-component>#{3} , <alpha-value> )
<hsl()> = hsl( <hue>, <percentage>, <percentage> )
<hsla()> = hsla( <hue>, <percentage>, <percentage>, <alpha-value> )
<named-color> = <ident>
<deprecated-system-color> = ActiveBorder | ActiveCaption | AppWorkspace | Background | ButtonFace | ButtonHighlight | ButtonShadow | ButtonText | CaptionText | GrayText | Highlight | HighlightText | InactiveBorder | InactiveCaption | InactiveCaptionText | InfoBackground | InfoText | Menu | MenuText | Scrollbar | ThreeDDarkShadow | ThreeDFace | ThreeDHighlight | ThreeDLightShadow | ThreeDShadow | Window | WindowFrame | WindowText
where 
<rgb-component> = <integer> | <percentage>
<alpha-value> = <number>
<hue> = <number>

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-rl;
  border-block-start: 5px dashed blue;
}

Specification

Browser compatibility

[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

• The mapped physical properties: border-top, border-right, border-bottom, and border-left
• writing-mode, direction, text-orientation