<!DOCTYPE html>
<html>
    <head>
        <title>CSS Reference File</title>
        <link rel="author" title="Rebecca Hauck" href="mailto:rhauck@adobe.com">
    </head>
    <style>
       body {
            margin: 0;
        }
       #green-square {
          position: absolute;
          top: 50px;
          left: 10px;
          width: 200px;
          height: 200px;
          background-color: green;
      }
    </style>
    <body>
        <p>The test passes if there is green square and no red.</p>
        <div id="green-square"></div>
    </body>
</html>