<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title>Document</title>
<style>
div{
width: 100px;
height: 100px;
background-color: red;
/* 外边距 */
margin-top: 30px;
margin-left: 100px;
margin-right: 100px;
margin-bottom: 100px;
/* 连写 */
margin: 40px;
margin: 0 auto;
/* 内边距 pandding */
padding: 30px;
}
</style>
</head>
<body>
<div>div第一个</div>
<div>div第二个</div>
</body>
</html>