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