有一个div,高度是自适应的,现在我想要这个div的宽度和高度一致,有什么办法?

    <div class="container">
        <div class="box"></div>
    </div>

方法一

        .container {
            height: 200px;
            width: 200px;
            background-color: blue;
        }

        .box{
            position: relative;
            width: 100px;
            height: 0;
            padding-bottom: 100px;
            background-color: red;
        }

方法二

        .container {
            height: 200px;
            width: 200px;
            background-color: blue;
        }

        .box {
            position: relative;
            width: 50%;
        }

        /* initial ratio of 1:1 */
        .box:before {
            content: "";
            display: block;
            padding-top: 100%;
        }

        /* initial ratio of 1:2 */
        .box:before {
            content: "";
            display: block;
            padding-top: 50%;
        }

        /* initial ratio of 2:1 */
        .box:before {
            content: "";
            display: block;
            padding-top: 200%;
        }