The block-size
CSS property defines the horizontal or vertical size of an element's block, depending on its writing mode. It corresponds to either the width
or the height
property, depending on the value of writing-mode
.
If the writing mode is vertically oriented, the value of block-size
relates to the width of the element; otherwise, it relates to the height of the element. A related property is inline-size
, which defines the other dimension of the element.