line-height can be inherited, when the set line-height without setting height, height value equal to line-height, in the following code, id is the height div the nav is equal to 50px, and for a label said line-height automatically inherit the attributes div, line-height and thus the height of a height equal to 50px tag, but before conversion to the height of two block-level element does not function, and is converted to the block level after the elements have a height of action, and therefore may not need to set the height of a label.
