title: 100% Css-layout with header and footer
body: <p>I'm trying to create a layout with a header and footer (both of which have a fixed heights) and a content-div between them that is fills the remaining space. Within the content-div I want to have divs with heights that are based on percent values (with the content-div's heihgt as parent). I can't figure out how to do this?</p>
  
  <p>Here is an illustration of what I'm trying to accomplish.
  <a href="https://i.stack.imgur.com/sfyuV.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/sfyuV.png" alt="layout example"></a>
  </p>