title: Odd centering CSS problem in modern non-Chrome browsers?
body: <p>For some reason, I have this one webpage which renders something great in Chrome, but completely different on FireFox and IE.</p>
  
  <p>The effect may be seen <a href="http://www.tiletabs.com/v2.htm" rel="nofollow">here</a>.</p>
  
  <p>The other browsers appear to remove my margin centering of my <code>header</code> and <code>footer</code> elements.</p>
  
  <p>Is there a particular reason this is only working in Chrome?</p>
  
  <p>Here is my HTML:</p>
  
  <pre><code>&lt;!DOCTYPE html&gt;
  
  &lt;html lang="en"&gt;
  &lt;head&gt;
      &lt;meta charset="utf-8"&gt;
      &lt;title&gt;TileTabs&lt;/title&gt;
  
      &lt;link rel="shortcut icon" type="image/x-icon" href="images/favicon/favicon.ico"&gt;
      &lt;link rel="stylesheet" href="css/v2.css" type="text/css"&gt;
      &lt;link rel="stylesheet" href="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.8/themes/base/jquery-ui.css" type="text/css"&gt;
      &lt;link rel="stylesheet" href="css/veramono.css" type="text/css"&gt;
  
      &lt;script src="https://ajax.googleapis.com/ajax/libs/jquery/1.4.4/jquery.min.js"&gt;&lt;/script&gt;
      &lt;script src="https://ajax.googleapis.com/ajax/libs/jqueryui/1.8.8/jquery-ui.min.js"&gt;&lt;/script&gt;
      &lt;script src="js/tile_interaction.js"&gt;&lt;/script&gt;
  &lt;/head&gt;
  &lt;body&gt;
      &lt;header&gt;
          &lt;img src="images/logo/logo_v3.png" alt="logo" /&gt;
      &lt;/header&gt;
  
      &lt;div id="content"&gt;
          &lt;ul&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
              &lt;li&gt;
                  &lt;div class="tile"&gt;
                  &lt;/div&gt;
              &lt;/li&gt;
          &lt;/ul&gt;
      &lt;/div&gt;
  
      &lt;footer&gt;
          &lt;a class="emailus" href="index.htm"&gt;Home&lt;/a&gt; | &lt;a class="emailus" href="about.htm"&gt;About&lt;/a&gt; | &lt;a class="emailus" href="contact.htm"&gt;Contact&lt;/a&gt;
      &lt;/footer&gt;
  &lt;/body&gt;
  &lt;/html&gt;
  </code></pre>
  
  <p>CSS:</p>
  
  <pre><code>body {
      background: #F6F6F6;
      font-family: 'BitstreamVeraSansMonoRoman', 'Myriad-Pro', 'Myriad', helvetica, arial, sans-serif;
      margin: 0;
  }
  
  a:link, a:visited, a:hover, a:active {
      color: white;
      text-decoration: none;
  }
  
  header {
      width: 920px;
      background: #999;
      margin: 0px auto;
      text-align: center;
  
      -webkit-border-top-left-radius: 20px;
      -webkit-border-top-right-radius: 20px;
      -moz-border-radius-topleft: 20px;
      -moz-border-radius-topright: 20px;
      border-top-left-radius: 20px;
      border-top-right-radius: 20px;
  
  
  }
  
  #content {
      width: 920px;
      height: 760px;
      background: #999;
      margin: 0px auto;
  }
  
  footer {
      width: 920px;
      background: #999;
      margin: 0px auto;
      text-align: center;
      padding-top: 10px;
      padding-bottom: 10px;
  
      -webkit-border-bottom-right-radius: 20px;
      -webkit-border-bottom-left-radius: 20px;
      -moz-border-radius-bottomright: 20px;
      -moz-border-radius-bottomleft: 20px;
      border-bottom-right-radius: 20px;
      border-bottom-left-radius: 20px;    
  }
  
  li {
      float: left;
      list-style: none;
      padding: 34px;
  }
  
  .tile {
      cursor: pointer;
      background: red;
      border: 2px solid #000;
      width: 100px;
      height: 100px;
  }
  </code></pre>