css/css-multicol/multicol-span-all-margin-nested-001.xht

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
 <head>
  <title>CSS Multi-column Layout Test: vertically adjacent spanning elements with nested margins (complex)</title>
  <link rel="author" title="Opera Software ASA" href="http://www.opera.com/" />
  <link rel="reviewer" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/" /> <!-- 2013-08-19 -->
  <link rel="help" href="http://www.w3.org/TR/css3-multicol/#column-span" title="6.1. 'column-span'" />
  <link rel="match" href="multicol-span-all-margin-nested-001-ref.xht" />
  <meta name="flags" content="ahem" />
  <meta name="assert" content="In this test, the first h4 element would collapse its margin bottom with the top margin of div#child if only div#child was also a spanning element, which is not: the bottom margin of the first h4 element is 8em wide while the top margin of div#child is only 2em wide (1 column box wide). That is why the bottom margin of the first h4 element should not collapse with the top margin of div#child." />
  <link rel="stylesheet" type="text/css" href="/fonts/ahem.css" />
  <style type="text/css"><![CDATA[
  div#multi-column
  {
  background-color: yellow;
  border: gray solid 1em;
  color: navy;
  font: 1.25em/1 Ahem;
  orphans: 1;
  overflow: hidden;
  widows: 1;
  width: 8em;

  column-count: 4;
  column-gap: 0em;

  /*

  N == 4;

  W == 2em;

  */
  }

  h4, div#child
  {
  background-color: black;
  color: black;
  font: inherit;
  margin: 0;
  }

  h4
  {
  margin: 1em 0;
  width: 11em;

  column-span: all;
  }
  ]]></style>
 </head>
 <body>

  <div id="multi-column">
    na vy na vy
    na vy na vy

    <h4 id="first">black</h4>

    <div id="child">
      <h4 id="nested">black</h4>
    </div>

    na vy na vy
    na vy na vy
  </div>

 </body>
</html>