<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box1{
            width: 200px;
            height: 200px;
            background: green;
            border: 5px solid blue;
            /* padding-top: 10px;
            padding-left: 10px; */
            padding: 10px;
        }
        .box2{
            width: 100px;
            height: 150px;
            background:red;
        }
        .box3{
            width: 50px;
            height: 50px;
            background:gray;
            margin-top: 10px;
        }
        .box4{
            width: 50px;
            height: 50px;
            background:brown;
            border: 10px solid red;
            padding-top: 10px;
        }
    </style>
</head>
<body>
    <!-- 盒子模型只要是设置4部分内容
        1、内容大小(width,height)
        2、边框大小(border)
        3、内边距大小(padding)
        4、外边距大小(margin) -->

    <div class="box1">
        <div class="box2"></div>
    </div>
    <div class="box3"></div>
    <div class="box4"></div>
</body>
</html>