html,body{margin: 0;padding:0; background-color:#ffffff; }
    DIV.outer
      {
      position: absolute;
      left: 50%;
      top: 50%;
      width: 800px;
      height: 600px;
     margin-left: -400px; /* half of width */
      margin-top: -300px;  /* half of height */
      
      }