border-block-start-width

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since ⁨January 2020⁩.

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

Try it

Syntax

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

Values

<'border-width'>

The width of the border. See border-width.

Formal definition

Initial valuemedium
Applies toall elements
Inheritedno
Percentageslogical-width of containing block
Computed valueabsolute length; 0 if the border style is none or hidden
Animation typeby computed value type

Formal syntax

border-block-start-width = 
<line-width>

<line-width> =
<length [0,∞]> |
thin |
medium |
thick

Examples

Border width with vertical text

HTML

CSS

Results

Specifications

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

Browser compatibility

See also