<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="utf-8">

  <style>
    body {
      width: 100%;
      height: 100%;
    }

    div {
      position: absolute;
      height: 100px;
      width: 500px;
    }

    #bottom {
      bottom: 0px;
    }

    #vertical {
      height: 100%;
    }

    #farbottom {
      top: 2000px;
      background: red;
    }

    #abovetop {
      top: -123px;
    }";
  </style>
</head>
<body>
  <div id="abovetop"></div>
  <div id="vertical"></div>
  <div id="top" class="class1 class2"></div>
  <div id="bottom"></div>
  <div id="farbottom"></div>
</body>
</html>
