css 使用百分比设置margin

编辑代码

<!DOCTYPE html>
<html>
<head>
<style>
p.bottommargin {margin-bottom:25%;}
</style>
</head>
<body>

<p>This is a paragraph with no margin specified.</p>
<p class="bottommargin">This is a paragraph with a specified bottom margin.</p>
<p>This is a paragraph with no margin specified.</p>

</body>
</html>