要为超链接设置不同的样式，例如字体大小，背景颜色等，您可以尝试运行以下代码：
<!DOCTYPE html>
<html>
<head>
<style>
a.first:link {color:#ff0000;}
a.first:visited {color:#0000ff;}
a.first:hover {color:#ffcc00;}
a.second:link {color:#ff0000;}
a.second:visited {color:#0000ff;}
a.second:hover {font-size:150%;}
a.third:link {color:#ff0000;}
a.third:visited {color:#0000ff;}
a.third:hover {background:#66ff66;}
</style>
</head>
<body>
<p>Mouse over the below given links:</p>
<p><b><a class = "first" href = "demo1.html" target = "_blank">Link changes color</a></b></p>
<p><b><a class = "second" href = "demo2.html" target = "_blank">Link changes font-size</a></b></p>
<p><b><a class = "third" href = "demo3.html" target = "_blank">Link changes background-color</a></b></p>
</body>
</html>