title: Centering a percent-based div
body: <p>Recently, a client asked that his site be percent-based rather than pixel-based. The percent was to be set to 80%. As you guys know, it is very easy to center the container if it is pixel-based but how do you center a percent-based main container?</p>
  
  <pre><code>#container
  {
    width:80%;
    margin:0px auto;
  }
  </code></pre>
  
  <p>That does not center the container :(</p>