如何保证浮层不被隐藏
描述不清楚，代码贴出来了，求解决
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>测试</title>
<style>
body{background:url(http://www.google.com.hk/intl/zh-CN/images/logo_cn.png);}
ol,ul,dd,dl{list-style:none;padding:0;margin:0;}
.main{border::1px solid #dacfad;float:left;position:relative;overflow:hidden;min-height:300px;}
.main_content{position:relative;z-index:1;}
.fixopacity {width:1000px;height:20000px;position:absolute;top:0;left:0;filter:alpha(opacity=65);opacity:0.65;background:#FDF3E7;}
.main{width:680px;}
.hallList{padding:20px 0 0 5px;float:left;}
.hallList li{float:left;border:1px solid #CABAAD;padding:5px;margin:2.5px;width:150px;line-height:20px;position:relative;z-index:1;}
.hallList img{float:left;}
.hallList .hallActive{z-index:2;}
.hallList p{float:left;}
.hallList .shop_pic{padding-bottom:3px;position:relative;z-index:2;}
.hallList li:hover .shopTip{display:block;}
.hallList .shopTip{position:absolute;top:30px;left:60px;z-index:3;width:310px;}
.hallList .shopTip dl{background:#F9DFDC;width:290px;;float:left;height:100px;}
.hallList .shopTip dd{padding:0 10px;color:#4c4101;line-height:1.4em;float:left;width:270px;}
</style>
</head>
<body>
<div class="main">
<div class="main_content">
<ul class="hallList">
<li><img class="shop_pic" src="http://wenwen.soso.com/p/20100420/20100420190545-550986757.jpg" width="150px" height="150px"/></li>
<li><img class="shop_pic" src="http://wenwen.soso.com/p/20100420/20100420190545-550986757.jpg" width="150px" height="150px"/></li>
<li><img class="shop_pic" src="http://wenwen.soso.com/p/20100420/20100420190545-550986757.jpg" width="150px" height="150px"/></li>
<li class="hallActive"><img class="shop_pic" src="http://wenwen.soso.com/p/20100420/20100420190545-550986757.jpg" width="150px" height="150px"/>
<div class="shopTip"><dl><dd>这是浮层这是浮层这是浮层这是浮层</dd></dl></div></li>
</ul>
</div>
<div class="fixopacity"></div>
</div>
</body>
</html>
[解决办法]
用FIREBUG看一下不就知道了
