<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title></title>
<style type="text/css">
.left{
height: 300px;
width: 200px;
background: red;
float: left;
/*opacity: 0.5;*/
}
.right{
height: 300px;
background: blue;
margin-left: 200px;
/*width: 100%;*/
}
.main{
width: 80%;
margin: auto;
}
</style>
</head>
<body>
<div class="main">
<div class="left"></div>
<div class="right"></div>
</div>
</body>
</html>
