请大家给我看看这个下拉菜单到底怎么了
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a{ text-decoration:none;}#bar{ width:100%; height:40px; z-index:999; padding-top:5px; background:url(bar_bg.gif) repeat-x; }#nav{ width:960px; height:30px; margin:0 auto; }#nav ul { padding:0; margin:0; list-style-type: none; }#nav ul li{ list-style:none; float:left; position:relative; width:100px; }#nav ul li a{ display:block; text-align:center; line-height:28px; padding-left:9px; padding-right:9px; color:#bdbde2; height:30px; }#nav ul li:hover a{ background-color:#000066; color:#00FF99; }#nav ul li ul { display: none; }#nav ul li:hover ul { display:block; top:30px; position:absolute; width:80px; color:#00FF99; text-align:center; }#nav ul li:hover ul li { background-color:#333333; display:block; color:#bdbde2; height:28px; padding-top:4px; width:100px; }#nav ul li:hover ul li a { display:block; color:#bdbde2; background:#1C5579; }#nav ul li:hover ul li a:hover { background-color:#000066; color:#00FF99; }