body {
            font-family: Arial, sans-serif;
            margin: 0;
            padding: 20px;
            background-color: #f5f5f5;
        }
        .container {
            max-width: 800px;
            margin: 0 auto;
            background-color: white;
            padding: 20px;
            border-radius: 8px;
            box-shadow: 0 2px 10px rgba(0,0,0,0.1);
        }
        h1 {
            text-align: center;
            color: #333;
        }
        .content {
            margin-top: 20px;
            line-height: 1.6;
            color: #555;
        }
        .loading {
            text-align: center;
            padding: 40px 0;
            color: #999;
        }
        .back-btn {
            display: block;
            width: 200px;
            margin: 30px auto 0;
            padding: 10px;
            text-align: center;
            background-color: #4CAF50;
            color: white;
            text-decoration: none;
            border-radius: 4px;
            transition: background-color 0.3s;
        }