<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0//EN">
<html lang="en">
 <head>
  <title>Margin Collapsing: top margins</title>
  <style type="text/css">
   .test { background: aqua; margin: 0; width: 6em; border: solid; }
   .test .a { height: 1em; background: fuchsia; margin: 0; }
   .test .b { background: red; margin: 0; }
   .test .c { float: left; height: 1em; width: 3em; background: orange; margin: 0; }
   .test .d { height: 1em; background: yellow; margin: 1em 0 0 0; }
   .control { width: 6em; border: solid; }
   .control .a { border-top: fuchsia 1em solid; }
   .control .b { border-top: aqua 1em solid; }
   .control .c { border-left: orange 3em solid; border-right: yellow 3em solid; height: 1em; }
  </style>
 </head>
 <body>
  <p>The two boxes below should look identical.</p>
  <table>
   <tr>
    <td>
     <div class="test">
      <div class="a"></div>
      <div class="b">
       <div class="c"></div>
       <div class="d"></div>
      </div>
     </div>
    </td>
    <td>
     <div class="control">
      <div class="a"></div>
      <div class="b"></div>
      <div class="c"></div>
     </div>
    </td>
   </tr>
  </table>
 </body>
</html>
