CSS仿淘宝首页导航条布局效果

以下是引用片段：
<style> 
/* www.zishu.cn 子鼠*/ 
body{ font-size:12px; text-align:center;  margin-top:30px; font-family:Verdana;} 
div,img{margin:0; padding:0; border:0;} 
ul,li{list-style-type: none; margin:0; padding:0; float:left; } 
#info{ margin-left:auto; margin-right:auto;width:760px; text-align:left;} 
#new{ margin-top:-12px;position: absolute;margin-left:-12px;} 
#nav{ height:30px; width:610px; margin-left:auto; margin-right:auto;} 
#nav li{margin-left:1px; height:30px;} 
#nav li a{ display:block;float:left; text-decoration:none; background-image: url(http://www.zishu.cn/attachments/month_0605/r200652134132.gif);background-repeat: no-repeat; display:block; background-position:left top;} 
#nav a span{cursor:hand; color:#000;background-image: url(http://www.zishu.cn/attachments/month_0605/v200652134115.gif);background-repeat: no-repeat; display:block;background-position: right top; padding:7px 10px 6px 10px; float:left; } 
#nav li a:active,#nav li a:hover {margin-top:0px; } 
#nav li  a:active span,#nav li a:hover span {padding:10px 10px 6px 10px; margin-top:0px; display:block; color:#FFF;} 
#zishu01 a:link,#zishu01 a:visited {background-position: 0px -27px;} 
#zishu01 a:link span,#zishu01 a:visited span{background-position:right -27px;padding:10px 10px 6px 10px; margin-top:0; color:#FFF; font-weight:bold;} 
#zishu02 a,#zishu03 a,#zishu04 a,#zishu05 a,#zishu06 a,#zishu07 a,#zishu08 a,#zishu09 a,#zishu10 a,#zishu11 a{margin-top:3px;} 
#zishu02 a:active,#zishu02 a:hover {background-position: 0px -57px;} 
#zishu02 a:active span,#zishu02 a:hover span{background-position:right -57px;} 
#zishu03 a:active,#zishu03 a:hover {background-position: 0px -87px;} 
#zishu03 a:active span,#zishu03 a:hover span{background-position:right -87px;} 
#zishu04 a:active,#zishu04 a:hover {background-position: 0px -117px;} 
#zishu04 a:active span,#zishu04 a:hover span{background-position:right -117px;} 
#zishu05 a:active,#zishu05 a:hover {background-position: 0px -147px;} 
#zishu05 a:active span,#zishu05 a:hover span{background-position:right -147px;} 
#zishu06 a:active,#zishu06 a:hover {background-position: 0px -177px;} 
#zishu06 a:active span,#zishu06 a:hover span{background-position:right -177px;} 
#zishu07 a:active,#zishu07 a:hover {background-position: 0px -207px;} 
#zishu07 a:active span,#zishu07 a:hover span{background-position:right -207px;} 
#zishu08 a:active,#zishu08 a:hover {background-position: 0px -237px;} 
#zishu08 a:active span,#zishu08 a:hover span{background-position:right -237px;} 
#zishu09 a:active,#zishu09 a:hover {background-position: 0px -267px;} 
#zishu09 a:active span,#zishu09 a:hover span{background-position:right -267px;} 
#zishu10 a:active,#zishu10 a:hover {background-position: 0px -297px;} 
#zishu10 a:active span,#zishu10 a:hover span{background-position:right -297px;} 
#zishu11 a:link span,#zishu11 a:visited span{color:#FF6600;} 
#zishu11 a:active,#zishu11 a:hover {background-position: 0px -327px;} 
#zishu11 a:active span,#zishu11 a:hover span{background-position:right -327px;} 
#menu{ width:760px; height:26px; background:#FF9900;} 
#r1{border-top: 0px;border-bottom: 0px; border-left:3px solid #fff;border-right:3px solid #fff; height:1px; overflow:hidden;} 
#r2{border-top: 0px;border-bottom: 0px; border-left:2px solid #fff;border-right:2px solid #fff; height:1px; overflow:hidden;} 
#r3{border-top: 0px;border-bottom: 0px;    border-left:1px solid #fff;border-right:1px solid #fff; height:1px; overflow:hidden;} 
</style>


     以下是内容部分：

以下是引用片段：
<div id="info"> 
    <div id="nav"> 
        <ul> 
            <li id="zishu01"><a href="http://www.zishu.cn"><span>首页</span></a></li> 
            <li id="zishu02"><a href="http://www.zishu.cn"><span>数码通讯</span></a></li> 
            <li id="zishu03"><a href="http://www.zishu.cn"><span>女人</span></a></li> 
            <li id="zishu04"><a href="http://www.zishu.cn"><span>男人</span></a></li> 
            <li id="zishu05"><a href="http://www.zishu.cn"><span>家居</span></a></li> 
            <li id="zishu06"><a href="http://www.zishu.cn"><span>书籍音像</span></a></li> 
            <li id="zishu07"><a href="http://www.zishu.cn"><span>运动</span></a></li> 
            <li id="zishu08"><a href="http://www.zishu.cn"><span>游戏</span></a></li> 
            <li id="zishu09"><a href="http://www.zishu.cn"><span>宠物</span></a></li> 
            <li id="zishu10"><a href="http://www.zishu.cn"><span>香港街</span></a></li> 
            <li id="zishu11"><a href="http://www.zishu.cn"><span>淘宝商城</span></a></li> 
            <li><div id="new"><img src="//www.zishu.cn/attachments/month_0605/x200652135342.gif" alt="新加栏目" /></div></li> 
        </ul> 
    </div>     
    <div id="menu"> 
        <div id="r1"></div> 
        <div id="r2"></div> 
        <div id="r3"></div> 
        <div></div> 
    </div> 
</div> 
<p>仿淘宝网首页导航条效果 转载请注明出处 子鼠 www.zishu.cn 2006-05-21 凌晨03:05分</p>