<!DOCTYPE html>
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .box{
            width: 200px;
            height: 200px;
            background: green;
            /* 设置背景图片，不重复显示图片，拉伸当前显示的图片 */
            /* background: url("./img/红旗H9-2.jpg") no-repeat; */
            /* 设置标签的四周边框 */
            border: 5px solid red ;
            border-top: 5px solid black;
            border-left: 5px solid black;
            border-bottom: 5px solid black;
            border-right: 5px solid black;
            /* 设置浮动，只能设置左浮动和右浮动 */
            /* float: right; */
        }
        .box1{
            width: 200px;
            height: 200px;
            background: blue;
        }
        .box2{
            width: 50px;
            height: 50px;
            background:green;
            float: left;
        }
        .box3{
            width: 50px;
            height: 50px;
            background: red;
            float: left;
        }
    </style>
</head>
<body>
    <!-- 布局常用控件是div  -->
    <div class="box">哈哈哈哈</div>
    <br>
    <div class="box1">
        <div class="box2"></div>
        <div class="box3"></div>
    </div>
</body>
</html>