转自司徒大人的佳作：http://www.cnblogs.com/rubylouvre/archive/2011/02/15/1955486.html
实质就是一个切换卡，关键是如何让鼠标从按钮移到面板上时，面板不会消失。用到div:hover与CSS3圆角
<!DOCTYPE HTML>
<html>
<head>
<title>纯CSS后台框架 by 司徒正美</title>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<style>
.main_console {
border-top:30px solid #c2e1f8;
padding: 40px;
background: #c2e1f8;
height:500px;
border-radius:10px;
position:relative;
}
.main_client {
position:absolute;
width:800px;
height:500px;
top:0;
left:150px;
z-index:1;
border-radius:10px;
background:#8ed2f3;
}
.column_title {
width:150px;
height:30px;
border-top:1px solid #fff;
border-left:1px solid #fff;
border-bottom:1px solid #3183a1;
line-height:30px;
text-align:center;
color:#3183a1;
font-size:12px;
}
.main_column:hover .column_title {
background:#8ed2f3;
color:#fff;
}
/*.main_panel_wraper的作用是用于防止它移到面板上时面板立即消失*/
.main_panel_wraper {
position:absolute;
left:148px;/*注意这里，一定要把它与main_column处于交集状态*/
top:0;
z-index:2;
display:none;
width:800px;
height:500px;
}
.main_column:hover .main_panel_wraper {
display:block;
}
/*真正用于放置内容的地方*/
.main_panel {
width:780px;
height:480px;
border-radius:10px;
margin:10px;
background:#dff9fb;
}
</style>
</head>
<body>
<div class="main_console">
<div class="main_column">
<div class="column_title">AAAAA</div>
<div class="main_panel_wraper">
<div class="main_panel">AAAA的面板</div>
</div>
</div>
<div class="main_column">
<div class="column_title">BBBB</div>
<div class="main_panel_wraper">
<div class="main_panel">BBBB的面板</div>
</div>
</div>
<div class="main_column">
<div class="column_title">CCCC</div>
<div class="main_panel_wraper">
<div class="main_panel">CCCC的面板</div>
</div>
</div>
<div class="main_column">
<div class="column_title">DDDD</div>
<div class="main_panel_wraper">
<div class="main_panel">DDDD的面板</div>
</div>
</div>
<div class="main_client"></div>
</div>
</body>
</html>