                        课程
                    
                        /前端开发
                        
                            /HTML/CSS
                        
                        /如何用CSS进行网页布局

为什么我输入的代码浏览器上没有颜色

<!DOCTYPE html>
<html lang="en" >
<head>
<meta charset="UTF-8" http-equiv="content-type " >
<title>布局</title>
</head>
<body>
<style type="text/css " >
body { margin: 0;padding: 0}
.main{ width:800px;height:300px;background:#cccccc; }
.top{height: 100px;background: blue;margin: 0 auto }
.foot{width:800px;height: 100px;background: #900;margin: 0 auto }

</style >

<div class="top"></div>
<div class="main"></div>
<div class="foot"></div>

</body>
</html>