在线运行代码 - 菜鸟教程

<html>
<head>
<style>body
{
font-size:50px;
}
</style>
</head>
<body>

<h1>This is a header (headers are not affected by the font-size property)</h1>
<p>This is a paragraph.</p>

</body>
</html>

源代码

动行结果