title: Auto adjust div height to fill space - CSS
body: <p>I have a top header <code>&lt;div id="header"&gt;&lt;/div&gt;</code>, a middle part <code>&lt;div id="content"&gt;&lt;/div&gt;</code> and a bottom footer <code>&lt;div id="footer"&gt;&lt;/div&gt;</code>. </p>
  
  <p>Header and footer has fixed heights 50px. I want to fix the positions of header and footer on top and bottom and I want to stretch the middle part (content) to fill the remaining space.</p>
  
  <p>How can I do this?</p>