Except that adjacent vertical margins collapse on each other, so the space is the larger of the 2 margin values not the sum. more info: http://reference.sitepo

Except that adjacent vertical margins collapse on each other, so the space is the larger of the 2 margin values not the sum. more info: http://reference.sitepoint.com/css/collapsingmargins http://reference.sitepoint.com/css/collapsingmargins This is not true of padding (unless you count a bug in IE8 where percentage-based padding-bottom collapses on the margin-bottom)