border-block-width

The border-block-width CSS property defines the width of the logical block borders 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 and border-bottom-width, or border-left-width, and border-right-width property depending on the values defined for writing-mode, direction, and text-orientation.

The border width in the other dimension can be set with border-inline-width, which sets border-inline-start-width, and border-inline-end-width.

Values: <line-width> Defines the width of the border, either as an explicit non-negative <length> or the keywords: thin, medium, or thick. The default is medium.

Syntax example: border-block-width: 5px;