* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'PingFang SC', 'Microsoft YaHei', sans-serif;
        }
         
        body {
            background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
            min-height: 100vh;
            display: flex;
            justify-content: center;
            align-items: center;
            padding: 20px;
        }
         
        .container {
            width: 100%;
            max-width: 500px;
            background: white;
            border-radius: 16px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }
         
        .header {
            background: #4a6bdf;
            color: white;
            padding: 25px 20px;
            text-align: center;
        }
         
        .header h1 {
            font-size: 24px;
            font-weight: 600;
        }
         
        .form-container {
            padding: 25px;
        }
         
        .form-group {
            margin-bottom: 20px;
        }
         
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            color: #333;
        }
         
        .form-group input {
            width: 100%;
            padding: 14px;
            border: 1px solid #ddd;
            border-radius: 8px;
            font-size: 16px;
            transition: border-color 0.3s;
        }
         
        .form-group input:focus {
            border-color: #4a6bdf;
            outline: none;
            box-shadow: 0 0 0 2px rgba(74, 107, 223, 0.2);
        }
         
        .btn {
            width: 100%;
            padding: 14px;
            background: #4a6bdf;
            color: white;
            border: none;
            border-radius: 8px;
            font-size: 16px;
            font-weight: 500;
            cursor: pointer;
            transition: background 0.3s;
        }
         
        .btn:hover {
            background: #3a5bce;
        }
         
        .btn:disabled {
            background: #b0b0b0;
            cursor: not-allowed;
        }
         
        .view {
            display: none;
        }
         
        .view.active {
            display: block;
            animation: fadeIn 0.3s ease;
        }
         
        @keyframes fadeIn {
            from { opacity: 0; }
            to { opacity: 1; }
        }
         
        .user-info {
            background: #f9f9f9;
            padding: 15px;
            border-radius: 8px;
            margin-bottom: 20px;
        }
         
        .user-info p {
            margin-bottom: 8px;
            color: #555;
        }
         
        .user-info span {
            font-weight: 500;
            color: #333;
        }
         
        .checkin-status {
            text-align: center;
            padding: 20px;
            border-radius: 8px;
            margin-bottom: 20px;
            font-weight: 500;
        }
         
        .checked-in {
            background: #e8f5e9;
            color: #2e7d32;
        }
         
        .not-checked-in {
            background: #fff3e0;
            color: #ef6c00;
        }
         
        .history {
            margin-top: 25px;
        }
         
        .history h3 {
            margin-bottom: 15px;
            color: #333;
            padding-bottom: 8px;
            border-bottom: 1px solid #eee;
        }
         
        .history-list {
            max-height: 200px;
            overflow-y: auto;
        }
         
        .history-item {
            padding: 12px 15px;
            background: #f9f9f9;
            border-radius: 8px;
            margin-bottom: 10px;
            display: flex;
            justify-content: space-between;
        }
         
        .history-date {
            color: #555;
        }
         
        .history-time {
            color: #888;
            font-size: 14px;
        }
         
        .alert {
            padding: 15px;
            border-radius: 8px;
            margin-bottom: 20px;
            font-size: 14px;
        }
         
        .alert-warning {
            background: #fff3e0;
            color: #ef6c00;
            border-left: 4px solid #ff9800;
        }
         
        .alert-info {
            background: #e3f2fd;
            color: #1565c0;
            border-left: 4px solid #2196f3;
        }
         
        .sms-config {
            background: #f9f9f9;
            padding: 15px;
            border-radius: 8px;
            margin-top: 20px;
            font-size: 14px;
        }
         
        .sms-config h4 {
            margin-bottom: 10px;
            color: #333;
        }
         
        .sms-config p {
            margin-bottom: 8px;
            color: #555;
        }
         
        @media (max-width: 600px) {
            .container {
                border-radius: 12px;
            }
             
            .header {
                padding: 20px 15px;
            }
             
            .form-container {
                padding: 20px 15px;
            }
        }