<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN"> <html lang="en"> <head> <title>Margin Collapsing: negative margins (easy)</title> <style type="text/css"> .ahem { display: inline; font: 1em/1 Ahem, sans-serif; background: red; color: white; } .test { border: solid; background: red; width: 5em; font: 1em/1em Ahem; } .test .a { height: 0; margin: 0 0 1em 0; background: red; color: lime; } .test .b { height: 1em; margin: 1em 0 0 0; background: lime; } </style> </head> <body> <div class="ahem">Ahem_font_required_for_this_test.</div> <p>There should be no red below.</p> <div class="test"> <p class="a">XXXXX</p> <p class="b"></p> </div> </body> </html>