Make the border around the winners visible, by typing the missing keyword.

<html>
 <head>
 <style>
.winner {
border: solid gold;
width: 255px;
    }
 </style>
 </head>
 <body>
  <h2>Women's Marathon Ranking</h2>
  <ol class="winner">
    <li>Jemima Jelgat Sumgong</li>
    <li>Eunice Jepkirui Kirwa</li>
    <li>Mare Dibaba</li>
  </ol>  
 </body>
</html>]]>

Make sure to type solid.