一、效果

二、代码
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<title>css布局训练-一列固定宽度且居中</title>
<style>
*{
padding: 0;
margin: 0;
}
.top,
.banner,
.main,
.footer {
width: 960px;
text-align: center;
margin: 0 auto;
margin-bottom: 10px;
border: 1px dashed #ccc;
}
.top {
height: 80px;
background-color: pink;
}
.banner {
height: 120px;
background-color: purple;
}
.main {
height: 500px;
background-color: hotpink;
}
.footer {
height: 150px;
background-color: black;
}
</style>
</head>
<body>
<div class="top">top</div>
<div class="banner">banner</div>
<div class="main">main</div>
<div class="footer">footer</div>
</body>
</html>