如何用css3实现当鼠标移进去时当前亮其他变灰的效果

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<script></script> 
<title>用css3实现鼠标移进去当前亮其他变灰</title> 
 
<style> 
*{margin: 0;padding: 0;font-size:12px;} 
.wrapper{border: 1px #708090 solid;width: 900px;margin: 100px auto;height: 300px;padding: 20px;border-radius: 8px;box-shadow: 2px 2px 6px #666,-2px -2px 6px #666;} 
li{list-style: none;} 
.box:hover li{opacity:0.2; } 
.box li{float: left;width:48px; height:48px;position:relative; margin-right:10px; 
-webkit-transition: opacity 1s ease-in-out; 
-moz-transition: opacity 1s ease-in-out; 
-ms-transition: opacity 1s ease-in-out; 
-o-transition: opacity 1s ease-in-out; 
transition: opacity 1s ease-in-out; 
} 
.box li:hover{opacity:1; } 
.box li a{position:absolute;left:-10px;width:80px;height:30px;top:-30px;color: #fff;font-weight:bold;background:#000;border-radius:8px;box-shadow:1px 0 2px #fff inset;text-align:center;opacity:0; 
-webkit-transition: opacity 1s ease-in-out; 
-moz-transition: opacity 1s ease-in-out; 
-ms-transition: opacity 1s ease-in-out; 
-o-transition: opacity 1s ease-in-out; 
transition: opacity 1s ease-in-out; 
} 
.box li:hover a{opacity:1; top:-30px;} 
.delicious { background-image:url("http://images.cnblogs.com/cnblogs_com/hxh-hua/478335/o_delicious.png"); } 
.digg { background-image:url("http://images.cnblogs.com/cnblogs_com/hxh-hua/478335/o_digg.png"); } 
.facebook { background-image:url("http://images.cnblogs.com/cnblogs_com/hxh-hua/478335/o_facebook.png"); } 
.flickr { background-image:url("http://images.cnblogs.com/cnblogs_com/hxh-hua/478335/o_digg.png"); } 
.linkedin { background-image:url("http://images.cnblogs.com/cnblogs_com/hxh-hua/478335/o_flickr.png"); } 
.box a{display: block;} 
</style> 
 
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