style type="text/css">
      .nav {
        width: 30%;
      }
      .main {
        width: 70%;
      }
    </style>
  </head>

  <body class="block-group">

      <div class="header block"><div class="box">Header</div></div>
      <div class="nav block"><div class="box">Nav</div></div>
      <div class="main block"><div class="box">Main</div></div>
      <div class="links block"><div class="box">Links</div></div>
      <div class="footer block"><div class="box">Footer</div></div>

  </body>

</html>
