<style type="text/css">

   * {
      margin:0px;
      padding:0px;
   }

   #header {
      margin:auto;
      width:500px;
      font-family:Arial, Helvetica, sans-serif;
   }

   ul, ol {
      list-style:none;
   }

   .nav > li {
      float:left;
   }

   .nav li a {
      background-color:blue;
      color:#FFFFFF;
      text-decoration:none;
      padding:3px 32px;
      display:block;
      font-size:14pt;
   }

   .nav li a:hover {
      background-color:#00aa7f;
   }

   .nav li ul {
      display:none;
      position:absolute;
      min-width:140px;
   }

   .nav li:hover > ul {
      display:block;
   }

   .nav li ul li {
      position:relative;
   }

   .nav li ul li ul {
      right:-140px;
      top:0px;
   }

</style>