<table>
  <tr>
    <td valign="top"><!-- Navigation --></td>
    <td valign="top"><!-- Content --></td>
  </tr>
</table>

.left { position:absolute; top:0; bottom:0; left:0; width:200px; }
.right { position:absolute; top:0; bottom:0; left:200px; right:0; }

<div class="left"><!-- Navigation --></div>
<div class="right"><!-- Content --></div>

.more {
background: rgba(0,255,0,.5);
padding:10px;
overflow: auto;
}