I would like the dropdown menu on this page - http://iphonebuy-host1.gaiahost.net/index.html - to be structured so that there are two lists side by side, with CDMA being the heading for one list and AT&T GSM being the heading for the other list. The thing is I want to have that box-shadow around both lists together - if I just turn them into two separate lists in my HTML, currently the CSS will put a box-shadow around each list separately.

Can I make them display in the same container as two lists side by side? I know I've seen it on other sites (wish I could find an example right now) but don't know if they used CSS or jQuery/JS.

HTML Code:
<ul class="topnav">
      <li><a href="index.html" class="vertical-line">Home</a></li> 
      <li><a href="#" class="vertical-line">Get Quote</a>
	     <ul>
	      <li><span>Choose your phone</span></li>
		  <li>CDMA</li>
		  <li><a href="cdma3gs8gb">3GS 8GB</a></li>
		  <li><a href="cdma3gs16gb">3GS 16GB</a></li>
		  <li><a href="cdma4-8gb">4 8GB</a></li>
		  <li><a href="cdma4-16gb">4 16GB</a></li>
		  <li><a href="cdma4s16gb">4S 16GB</a></li>
		  <li><a href="cdma4s32gb">4S 32GB</a></li>
		  <li>AT&amp;T GSM</li>
		  <li><a href="att3gs8gb">3GS 8GB</a></li>
		  <li><a href="att3gs16gb">3GS 16GB</a></li>
		  <li><a href="att4-8gb">4 8GB</a></li>
		  <li><a href="att4-16gb">4 16GB</a></li>
		  <li><a href="att4s16gb">4S 16GB</a></li>
		  <li><a href="att4s32gb">4S 32GB</a></li>
	    </ul>
	  </li>
      <li><a href="about.html">About</a></li>
    </ul>
Code:
/** top navigation menu **/
  .topnav {
    list-style:none;
    background-color:#FFF;
    font:1.313em arial, sans-serif;
    color:#0071BC;
    margin:-1.8em 0 1.2em 25em;
    text-align:center;
  }
  
  .topnav li {
    position:relative;
    display:inline;
    padding:0 .5em 0 .5em;
  }
  
  .topnav a { 
    display:inline-block;
  }
  
/** for drop-down menu **/
  .topnav ul {
    background:#fff;
    list-style:none;
    position:absolute;
    font:.9em arial, sans-serif;
    padding:.5em 0;
    left:-9999px;
    border-radius:.5em;
    -moz-box-shadow:    0 3px 2px 1px #ccc;
    -webkit-box-shadow: 0 3px 2px 1px #ccc;
    box-shadow:         0 3px 2px 1px #ccc;
  }  
  
  .topnav ul li {
    float:none;
    color:#95DF00;
  }
  
  .topnav ul li span {
    text-decoration:underline;
    white-space:nowrap;
  }
  
  .topnav ul a {
    white-space:nowrap;
    padding-top:.5em;
  }
  
  .topnav li:hover ul {
    left:0;
  }
  
  .topnav li:hover a {
    color:#99CCCC;
  }

  .topnav li:hover ul a {
    color:#0071BC;
  }
  
  .topnav li:hover ul a:hover {
    color:#99CCCC;
  }