<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>两列自适应布局</title>
<style type="text/css">
.out{
width: 90%;
height: 500px;
margin: 0 auto;
background: yellow;
}
.left{
width: 20%;
background: blue;
float: left;
height: 500px;
}
.right{
width: 80%;
background: red;
float: left;
height: 500px;
}
</style>
</head>
<body>
<div class="out">
<div class="left"></div>
<div class="right"></div>
</div>
</body>
</html>
原文：http://www.cnblogs.com/lhl66/p/7160008.html