怎么实现 文字不透明啊
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.<html xmlns="http://www.
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<style type="text/css">
<!--
#tt {
background-color: #FFCC66;
height: 100px;
width: 300px;
z-index: 3;
position: absolute;
left: 227px;
top: 65px;
}
#yy {
background-color: #009999;
height: 100px;
width: 200px;
display: block;
z-index: 1;
position: absolute;
}
#Layer1 {
position:absolute;
left:165px;
top:102px;
width:72px;
height:60px;
z-index:6;
background-color: #FFCCCC;
filter:alpha(opacity=50);
}
#u {
color: #000000;
position: relative;
}
-->
</style>
</head>
<body>
<div id="Layer1">
<div id="u">sdfsdfs</div>
</div>
<div id="tt">sadf</div>
<div id="yy">sadfff</div>
</body>
</html>