The max-block-size CSS property specifies the maximum size of an element in the direction opposite that of the writing direction as specified by writing-mode. That is, if the writing direction is horizontal, then max-block-size is equivalent to max-height; if the writing direction is vertical, max-block-size is the same as max-width....horizontal-tb , lr , lr-tb , rl , rb , rb-rl max-height vertical-rl ...modes lr , lr-tb , rl , rb , and rb-tl are no longer allowed...