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border-block-start-color

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-color, border-right-color, border-bottom-color, or border-left-color property depending on the values defined for writing-mode, direction, and text-orientation.

Try it

Syntax

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

/* Global values */
border-block-start-color: inherit;
border-block-start-color: initial;
border-block-start-color: revert;
border-block-start-color: revert-layer;
border-block-start-color: unset;

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

Values

<color>: The color of the border.

Formal definition

Initial value	`currentcolor`
Applies to	all elements
Inherited	no
Computed value	computed color
Animation type	a color

Formal syntax

border-block-start-color = 
  <'border-top-color'>

Examples

Border color with vertical text

HTML

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

CSS

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

.exampleText {
  writing-mode: vertical-lr;
  border: 10px solid blue;
  border-block-start-color: red;
}

Results

Specifications

Specification
CSS Logical Properties and Values Level 1 # border-color

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
`border-block-start-color`	69	79	41	No	56	12.1	69	69	41	48	12.2	10.0