title: Center DIV horizontally and fixed distance from top or bottom, no scrolling in window
body: <p>Say I have a div that I want to be centered horizontally, and set at a fixed distance from the top or bottom of the window.  I want to set its width to say 75%, and its height to be fluid depending on dynamic content. The page will never have content extending past the viewport so it won't ever scroll.  How can I do this with CSS?  HTML is here, basically:</p>
  
  <pre><code>&lt;body&gt;
    &lt;div id="main"&gt;
      &lt;div id="div_in_question"&gt;
        Omg stuff goes here it will probably change though via jQuery.
      &lt;/div&gt;
    &lt;/div&gt;
  &lt;/body&gt;
  </code></pre>