为什么按着老师讲的写 不出效果
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>无标题文档</title>
<link href="css/lcss.css" rel="stylesheet" type="text/css" media="only screen and(max-width:480px)"/>
<style>
@media screen and(min-width:480px){
body{background:blue;}
}
</style>
</head>
<body>
</body>
