body {
            font-family: Arial, sans-serif;
            text-align: center;
            margin-top: 50px;
            position: relative;
            min-height: 100vh; /* 保证页面内容占满整个页面 */
        }
        button {
            padding: 10px 20px;
            margin: 10px;
            font-size: 16px;
            cursor: pointer;
        }
        #result {
            margin-top: 20px;
            font-size: 18px;
        }
        .logo {
            position: absolute;
            top: -45px;
            left: -7px;
            width: 70px; /* LOGO的宽度 */
        }
        /* footer 样式 */
        footer {
            position: absolute;
            bottom: 70px;
            left: 0;
            right: 0;
            text-align: center;
            font-size: 12px;
            color: gray;
        }