为什么在里面那一层显示不了蓝色的背景
<html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en">
<head>
<meta http-equiv="content-type" content="text/html; charset=iso-8859-1" />
<meta name="author" content="Com" />
<title>无标题 1</title>
</head>
<style>
body{
background-color:red;
}
.content{
padding:40px;
float:left;
background-color:blue;
}
</style>
<body>
<div id="content">
<a>没有蓝色</a>
</div>
</body>
</html>
[解决办法]
