* {
            margin: 0;
            padding: 0;
            box-sizing: border-box;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
        }
        
        body {
            background-color: #f5f7fa;
            color: #333;
            line-height: 1.6;
            display: flex;
            justify-content: center;
            align-items: center;
            min-height: 100vh;
            padding: 20px;
        }
        
        .container {
            max-width: 500px;
            width: 100%;
            background: white;
            border-radius: 12px;
            box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
            overflow: hidden;
        }
        
        .header {
            background: linear-gradient(135deg, #3498db, #2c3e50);
            color: white;
            padding: 25px;
            text-align: center;
        }
        
        .header h1 {
            font-size: 24px;
            margin-bottom: 5px;
        }
        
        .header p {
            opacity: 0.9;
            font-size: 14px;
        }
        
        .payment-info {
            padding: 25px;
            border-bottom: 1px solid #eee;
        }
        
        .amount {
            font-size: 42px;
            font-weight: 700;
            text-align: center;
            color: #2c3e50;
            margin: 15px 0;
        }
        
        .amount span {
            font-size: 18px;
            color: #7f8c8d;
        }
        
        .payment-methods {
            padding: 20px 25px;
        }
        
        .payment-methods h2 {
            font-size: 18px;
            margin-bottom: 15px;
            color: #2c3e50;
        }
        
        .method-options {
            display: flex;
            gap: 15px;
            margin-bottom: 20px;
        }
        
        .method-option {
            flex: 1;
            border: 2px solid #e0e0e0;
            border-radius: 8px;
            padding: 15px;
            text-align: center;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .method-option:hover {
            border-color: #3498db;
        }
        
        .method-option.active {
            border-color: #3498db;
            background-color: #f0f8ff;
        }
        
        .method-option img {
            width: 40px;
            height: 40px;
            margin-bottom: 10px;
        }
        
        .method-option .method-name {
            font-weight: 600;
            font-size: 14px;
        }
        
        .payment-form {
            padding: 0 25px 25px;
        }
        
        .form-group {
            margin-bottom: 20px;
        }
        
        .form-group label {
            display: block;
            margin-bottom: 8px;
            font-weight: 500;
            color: #2c3e50;
        }
        
        .form-group input {
            width: 100%;
            padding: 12px 15px;
            border: 1px solid #ddd;
            border-radius: 6px;
            font-size: 16px;
            transition: border 0.3s;
        }
        
        .form-group input:focus {
            border-color: #3498db;
            outline: none;
        }
        
        .terms {
            display: flex;
            align-items: flex-start;
            gap: 10px;
            margin-bottom: 20px;
            font-size: 14px;
            color: #7f8c8d;
        }
        
        .terms input {
            margin-top: 3px;
        }
        
        .terms a {
            color: #3498db;
            text-decoration: none;
        }
        
        .pay-button {
            width: 100%;
            padding: 15px;
            background: linear-gradient(135deg, #3498db, #2980b9);
            color: white;
            border: none;
            border-radius: 6px;
            font-size: 16px;
            font-weight: 600;
            cursor: pointer;
            transition: all 0.3s;
        }
        
        .pay-button:hover {
            background: linear-gradient(135deg, #2980b9, #2573a7);
            transform: translateY(-2px);
            box-shadow: 0 5px 15px rgba(52, 152, 219, 0.3);
        }
        
        .pay-button:disabled {
            background: #bdc3c7;
            cursor: not-allowed;
            transform: none;
            box-shadow: none;
        }
        
        .security-note {
            text-align: center;
            padding: 15px;
            background: #f8f9fa;
            border-top: 1px solid #eee;
            font-size: 14px;
            color: #7f8c8d;
        }
        
        .security-note i {
            color: #27ae60;
            margin-right: 5px;
        }
        
        .success-modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0, 0, 0, 0.7);
            z-index: 1000;
            justify-content: center;
            align-items: center;
        }
        
        .success-content {
            background: white;
            border-radius: 12px;
            padding: 30px;
            text-align: center;
            max-width: 400px;
            width: 90%;
            animation: fadeIn 0.5s;
        }
        
        @keyframes fadeIn {
            from { opacity: 0; transform: translateY(-20px); }
            to { opacity: 1; transform: translateY(0); }
        }
        
        .success-icon {
            font-size: 60px;
            color: #27ae60;
            margin-bottom: 20px;
        }
        
        .success-content h2 {
            color: #2c3e50;
            margin-bottom: 15px;
        }
        
        .success-content p {
            margin-bottom: 20px;
            color: #7f8c8d;
        }
        
        .success-button {
            padding: 12px 25px;
            background: #3498db;
            color: white;
            border: none;
            border-radius: 6px;
            font-weight: 600;
            cursor: pointer;
            transition: background 0.3s;
        }
        
        .success-button:hover {
            background: #2980b9;
        }
        
        .error-message {
            color: #e74c3c;
            font-size: 14px;
            margin-top: 5px;
            display: none;
        }
        
        @media (max-width: 480px) {
            .method-options {
                flex-direction: column;
            }
            
            .header h1 {
                font-size: 20px;
            }
            
            .amount {
                font-size: 36px;
            }
        }