중앙정렬 메뉴구성하려면 ..

<style type="text/css">
#top-menu { height:35px; background:#0068b7; margin:0 auto; width:980px;}
ul#nav { float:left; font-weight:bold; margin:12px 10px 5px 15px; position:relative; list-style: none;}
ul#nav li { display: inline; }
ul#nav li a { height:35px; float: left; margin: 0; padding: 0 15px; color:#ffffff;}
ul#nav ul { display:none; }
ul#nav li:hover > ul { position:absolute; margin: 25px 0 0 0; left:-15px; background: #eaeaea; height: 30px; width:980px; z-index:10; display:block; }
ul#nav li:hover > ul li a { float: left; margin-left:15px; margin-top:8px; color:#444444; }
</style>

<div id="top-menu">
<ul id="nav">
<li name="menu">메뉴01</li>
<li name="menu">메뉴02</li>
<li name="menu">메뉴03</li>
<ul>

<li>서브메뉴01</li>
<li>서브메뉴02</li>
<li>서브메뉴03</li>

</ul>
</li>
</ul>
</div>

응용하세요 .