<!DOCTYPE html>

  <title>CSS Reftest Reference</title>

  <link rel="author" title="Gérard Talbot" href="http://www.gtalbot.org/BrowserBugsSection/css21testsuite/">

  <style>
  div#black-walls
    {
      border: solid 40px;
      border-color: transparent black;
      height: 400px;
      width: 400px;
    }

  div#inner-orange
    {
      background-color: orange;
      border: blue solid 16px;
      height: 368px; /*  400px - 2 * 16px == 368px  */
      margin: 0px auto;
      /* the orange block is horizontally centered inside div#black-walls */
      width: 168px;  /*  200px - 2 * 16px == 168px  */
    }
  </style>

  <div id="black-walls"><div id="inner-orange"></div></div>