body {
            padding: 0px;
            background-color: #f2f2f2;
            display: flex;
            flex-direction: column;
            min-height: 100vh;
        }
        .content-wrapper {
            flex: 1;
            margin: 20px 0; /* 添加上下边距 */
        }
        .container {
            max-width: 800px;
            margin: 0 auto;
            background-color: #fff;
            padding: 20px;
            border-radius: 5px;
            box-shadow: 0 0 10px rgba(0,0,0,0.1);
        }
        #countDownString {
            font-size: 80px;
            text-align: center;
            font-family: 'Arial', sans-serif;
            color: #333;
            margin: 20px 0;
        }
        .timer-controls {
            text-align: center;
            margin-top: 20px;
        }
        .progress-container {
            margin-top: 20px;
        }
        .page-title {
            text-align: center;
            margin-bottom: 30px;
            padding-bottom: 15px;
            border-bottom: 1px solid #eee;
            color: #333;
            font-size: 28px;
            font-weight: normal;
        }
        .instructions {
            margin-top: 40px;
            padding: 20px;
            background-color: #f8f8f8;
            border-radius: 5px;
            border-left: 4px solid #009688;
        }
        .instructions h2 {
            margin-bottom: 15px;
            color: #333;
            font-size: 20px;
        }
        .instructions ol {
            padding-left: 20px;
        }
        .instructions li {
            margin-bottom: 10px;
            line-height: 1.6;
        }