css font-size 设置字体大小

编辑代码
<!DOCTYPE html>
<html>
<head>
<style>
h1 {font-size:40px;}
h2 {font-size:30px;}
p {font-size:14px;}
</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 px allows Internet Explorer 9, Firefox, Chrome, Opera, 
and Safari to resize the text.</p>
<p><b>Note:</b> This example does not work in IE, prior version 9.</p>

</body>
</html>