<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8" />
<meta http-equiv="X-UA-Compatible" content="IE=edge" />
<meta name="viewport" content="width=device-width, initial-scale=1.0" />
<title>Document</title>
<style>
body {
padding: 100px;
}
div {
width: 300px;
height: 300px;
border: 2px solid #ddd;
box-shadow: 10px 10px rgba(100, 100, 100, .2); /*前两个参数 ：偏移量 rgba表示颜色带透明度*/
}
</style>
</head>
<body>
<article>
<div>helloworld</div>
</article>
</body>
</html>