css 使用百分比和EM组合设置字体大小

编辑代码

<!DOCTYPE html>
<html>
<head>
<style>
body {font-size:100%;}
h1 {font-size:2.5em;}
h2 {font-size:1.875em;}
p {font-size:0.875em;}
</style>
</head>
<body>

<h1>This is heading 1</h1>
<h2>This is heading 2</h2>
<p>This is a paragraph.</p>
<p>Specifying the font-size in percent and em displays the same size in all 
major browsers, and allows all browsers to resize the text!</p>

</body>
</html>