<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>CSS类选择器</title>
<style type="text/css">
.green{
color: green;
}
.big{
font-size: 40px;
}
</style>
</head>
<body>
<div class="big">
今天很开心
</div>
<br>
<div class="green">
今天很开心
</div>
<br>
<div id="" class="big green">
今天很开心
</div>
<br>
<p class="big">今天超级开心</p>
</body>
</html>
