<!DOCTYPE html>
<html>
<head>
<style>
div {
border: 1px solid black;
margin: 25px 50px;
background-color: lightblue;
}
</style>
</head>
<body>
<h1>简写属性 margin - 2 个值</h1>
<div>div 元素的上下外边距是 25 像素，左右外边距是 50 像素。</div>
<hr>
</body>
</html>