Center a <div> with Dynamic Height

gistfile1.html

<style>
  * {margin: 0; padding: 0;}
  #page {display:table; overflow:hidden; margin:0px auto;}
  *:first-child+html #page {position:relative;} /*ie7*/
  * html #page {position:relative;} /*ie6*/

  #content_container {display:table-cell; vertical-align: middle;}
  *:first-child+html #content_container {position:absolute; top:50%;} /*ie7*/
  * html #content_container {position:absolute; top:50%;} /*ie6*/

  *:first-child+html #content {position:relative;top:-50%;} /*ie7*/
  * html #content {position:relative;top:-50%;} /*ie6*/

  html, body {height:100%;}
  #page {height:100%; width:465px;}
</style>

<div id="page">
  <div id="content_container">
    <div id="content">
      <p>Your content.</p>
    </div>
  </div>
</div>