<html>
<head>
<style type="text/css">
h1.intro {color:blue;}
p.important {color:red;}
</style>
</head>
<body>
<h1 class="intro">Header 1</h1>
<p>A paragraph.</p>
<p class="important">请注意这个重要的段落。:)</p>
</body>
</html>