清除浮动-父级添加overflow（HTML、CSS）

<!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>清除浮动-父级添加overflow</title>
    <style>
        .box {

            overflow: hidden;
            /* 清除浮动 */
            width: 800px;
            border: 1px solid blue;
            margin: 0 auto;
        }

        .damao {
            float: left;
            width: 300px;
            height: 200px;
            background-color: purple;
        }

        .ermao {
            float: left;
            width: 200px;
            height: 200px;
            background-color: pink;
        }

        .footer {
            height: 200px;
            background-color: black;
        }
    </style>
</head>

<body>
    <div class="box">
        <div class="damao">大毛</div>
        <div class="ermao">二毛</div>
    </div>


    <div class="footer"></div>

</body>

</html>