Border Block Width

Set the vertical border width for an element.

Widely available

This feature is well established and works across many devices and browser versions.

Chrome
Edge
Firefox
Safari

byw-0
border-block-width: 0;
byw-1
border-block-width: 1px;
byw-2
border-block-width: 2px;
byw-3
border-block-width: 3px;
byw-4
border-block-width: 4px;
byw-5
border-block-width: 5px;
byw-6
border-block-width: 6px;
byw-7
border-block-width: 7px;
byw-8
border-block-width: 8px;

Responsiveness

Use breakpoint prefixes to target different screen sizes. Styles apply from the breakpoint & up.

Target viewport sizes with breakpoint prefixes.

sm:byw-(value)
Small≥640px
md:byw-(value)
Medium≥768px
lg:byw-(value)
Large≥1024px
xxl:byw-(value)
Extra Large≥1536px

Hover State

Apply styles conditionally on hover using the h: prefix.

Add the h: prefix to apply styles only when the user hovers over the element.

Syntax:h:byw-(value)

Negative Values

Use negative variants to apply negative border widths.

Use the -- syntax to apply negative numeric values.

Syntax:byw--(value)