title: How can an html element fill out 100% of the remaining screen height, using css only?
body: <p>I have a header element and a content element:</p>
  
  <pre><code>#header
  #content
  </code></pre>
  
  <p>I want the header to be of fixed height and the content to fill up all the remaining height available on the screen, with <code>overflow-y: scroll;</code>. </p>
  
  <p>It this possible without Javascript? </p>