<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: #00283a;
        color:#fff;
        text-decoration:none;
        padding:10px 53px;
        display:block;
      }
      
      .nav li a:hover {
        background-color:#92c517;
      }
      
      .nav li ul {
        display:none;
        position:absolute;
        min-width:200px;
      }
      
      .nav li:hover > ul {
        display:block;
      }
      
      .nav li ul li {
        position:relative;
      }
      
      .nav li ul li ul {
        right:-140px;
        top:0px;
      }
      
    </style>