效果图：
代码如下：
Title *{margin:0; padding:0; list-style:none;} ul{ overflow:hidden; background:#ccc; width:574px; margin:100px auto; position:relative;} ul li{ float:left; width:80px; height:40px; text-align:center; line-height:40px; border:1px solid #000; position:relative; z-index:2;} #block_box{ position:absolute; top:0; left:0; background:#399; z-index:1;}