title: Div Vertical Align Issue
body: <p>How can I set center for main div ? I will try many ways but I can't do it. Left and right seem okay. How can I change vertical position property ? I tried these:</p>
  
  <pre><code>margin-left:auto;
  margin-right:auto;
  margin-top:auto;
  margin-bottom:auto;
  
  vertical-align:middle;
  </code></pre>
  
  <p>These do not work.</p>
  
  <pre><code>#main 
   {
      width:1024px;
      height:600px;
      position:relative;
      z-index:1;
      margin:auto auto;
      text-align: center;
  
  
   }
  </code></pre>