ul#nav { 
 overflow: hidden; 
 width:650px;
 height:30px;
} 
 ul#nav li { 
 float: left; 
 list-style: none; 
 } 
 ul#nav li.backLava {
 margin-top:27px; 
 border-top:4px solid #36a5ff; 
 width: 9px; 
  z-index: 8; 
 position: absolute; 
 } 
 ul#nav li a { 
 font: bold 11pt 微软雅黑,幼圆; 
 line-height: 26px;
 text-decoration: none; 
 outline: none; 
 text-align: center; 
 text-transform: uppercase; 
 letter-spacing: 0; 
 z-index: 10; 
 display: block; 
 float: left; 
 position: relative; 
 overflow: hidden; 
 margin: auto 10px; 
 } 
 ul#nav li a:hover, ul#nav li a:active, ul#nav li a:visited { 
 border: none; 
 } �