:root {
            --primary: #3498db;
            --success: #27ae60;
            --danger: #e74c3c;
            --text: #2c3e50;
            --gray: #64748b;
            --border: #e2e8f0;
        }

        body {
            font-family: 'Segoe UI', system-ui, sans-serif;
            max-width: 650px;
            margin: 1rem auto;
            padding: 0 1rem;
            background: #f8fafc;
            line-height: 1.4;
        }

        .header {
            background: linear-gradient(135deg, var(--primary), #2980b9);
            color: white;
            padding: 1.2rem;
            border-radius: 12px 12px 0 0;
            text-align: center;
            font-size: 1.4rem;
            font-weight: 600;
            box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
        }

        .card {
            background: white;
            padding: 1.5rem;
            border-radius: 0 0 12px 12px;
            box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
            margin-bottom: 1.5rem;
        }

        .option-group {
            margin-bottom: 1.5rem;
            background: #f8fafc;
            border-radius: 8px;
            padding: 0.8rem;
        }

        .option-title {
            color: var(--text);
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 0.8rem;
            padding-left: 0.5rem;
            border-left: 4px solid var(--primary);
        }

        label {
            display: flex;
            align-items: center;
            padding: 0.8rem;
            margin: 0.3rem 0;
            border-radius: 8px;
            background: white;
            transition: all 0.2s;
            cursor: pointer;
            border: 2px solid transparent;
            flex-wrap: wrap;
        }

        label:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 6px -1px rgba(52,152,219,0.15);
            border-color: var(--primary);
        }

        input[type="radio"] {
            width: 18px;
            height: 18px;
            margin-right: 0.8rem;
            accent-color: var(--primary);
        }

        .price {
            margin-left: auto;
            color: var(--success);
            font-weight: 600;
            font-size: 1rem;
        }

        .input-field {
            width: 92%;
            padding: 0.7rem 0.9rem;
            margin-top: 0.7rem;
            border: 2px solid var(--border);
            border-radius: 8px;
            font-size: 0.95rem;
            transition: all 0.2s;
        }

        .input-field:focus {
            border-color: var(--primary);
            box-shadow: 0 0 0 3px rgba(52,152,219,0.2);
            outline: none;
        }

        #totalPrice {
            font-size: 1.5rem;
            color: var(--text);
            text-align: right;
            margin: 1.5rem 0;
            font-weight: 600;
        }

        .btn {
            background: linear-gradient(135deg, var(--primary), #2980b9);
            color: white;
            border: none;
            padding: 1rem;
            border-radius: 8px;
            cursor: pointer;
            width: 100%;
            font-size: 1rem;
            font-weight: 600;
            transition: transform 0.2s, box-shadow 0.2s;
        }

        .btn:hover {
            transform: translateY(-2px);
            box-shadow: 0 4px 6px -1px rgba(52,152,219,0.4);
        }

        .notice {
            text-align: center;
            color: var(--gray);
            font-size: 0.85rem;
            margin-top: 0.8rem;
            opacity: 0.9;
            line-height: 1.5;
        }

        .refs {
            color: var(--gray);
            font-size: 0.8rem;
            margin-bottom: 0.9rem;
            opacity: 0.9;
        }
        
        .payment-modal {
            display: none;
            position: fixed;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background: rgba(0,0,0,0.5);
            backdrop-filter: blur(4px);
            z-index: 1000;
            overflow-y: auto;
            padding: 1rem;
            box-sizing: border-box;
        }

        .payment-content {
            background: white;
            width: 100%;
            max-width: 500px;
            margin: 1rem auto;
            padding: 1.5rem;
            border-radius: 12px;
            box-shadow: 0 10px 15px -3px rgba(0,0,0,0.1);
            position: relative;
        }

        .payment-header {
            display: flex;
            justify-content: space-between;
            align-items: center;
            margin-bottom: 1.2rem;
        }

        .payment-header span {
            font-size: 1.1rem;
            font-weight: 600;
        }

        .countdown {
            color: var(--danger);
            font-weight: 600;
            font-size: 0.95rem;
        }

        .order-details {
            background: #f8fafc;
            border-radius: 8px;
            padding: 1rem;
            margin: 1.2rem 0;
        }

        .detail-item {
            display: flex;
            justify-content: space-between;
            padding: 0.5rem 0;
            border-bottom: 1px solid #e2e8f0;
            font-size: 0.95rem;
        }

        .detail-item:last-child {
            border-bottom: none;
        }

        .detail-item span {
            color: var(--gray);
        }

        .detail-item strong {
            color: var(--text);
            font-weight: 600;
        }

        .detail-item.total strong {
            color: var(--success);
            font-size: 1.1rem;
        }

        .payment-methods {
            display: grid;
            grid-template-columns: repeat(2, 1fr);
            gap: 0.8rem;
            margin: 1rem 0;
        }

        .payment-subtitle {
            color: var(--text);
            font-size: 1rem;
            font-weight: 600;
            margin-bottom: 0.8rem;
            padding-left: 0.5rem;
            border-left: 3px solid var(--primary);
        }

        .payment-method {
            padding: 0.8rem;
            height: 70px;
            border: 2px solid #e2e8f0;
            border-radius: 8px;
            cursor: pointer;
            text-align: center;
            transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
        }

        .payment-method:hover {
            transform: translateY(-3px);
            box-shadow: 0 4px 6px -1px rgba(52,152,219,0.15);
        }

        .payment-method.active {
            border-color: var(--primary);
            background: #f8fafc;
        }

        .payment-method img {
            width: 50px;
            height: 50px;
            margin-bottom: 0.3rem;
        }

        .payment-method div {
            font-size: 0.85rem;
        }

        .qrcode-container {
            position: relative;
            min-height: 180px;
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            margin: 0.5rem 0 1rem;
        }

        .qrcode-image {
            width: 180px;
            height: 180px;
            border: 1px solid var(--border);
            border-radius: 8px;
            padding: 0.8rem;
            background: white;
            box-shadow: 0 4px 6px -1px rgba(0,0,0,0.05);
            display: none;
        }

        .loading-container {
            display: none;
            flex-direction: column;
            align-items: center;
            gap: 0.8rem;
            position: absolute;
        }

        .qrcode-container.loading .loading-container {
            display: flex;
        }

        .qrcode-container.loaded .qrcode-image {
            display: block;
        }

        .payment-tip {
            display: none;
            text-align: center;
            margin-top: 12px;
            padding: 8px 12px;
            background-color: #f8f9fa;
            border-radius: 8px;
            color: var(--gray);
            font-size: 0.85rem;
            border: 1px solid var(--border);
            max-width: 90%;
        }

        .payment-actions {
            display: flex;
            gap: 0.8rem;
            margin-top: 1.5rem;
        }

        .btn-secondary {
            background: linear-gradient(135deg, var(--gray), #475569);
        }

        .error-message {
            color: #e74c3c;
            padding: 0.7rem;
            background: #f8d7da;
            border-radius: 6px;
            margin: 0.8rem 0;
            display: none;
            font-size: 0.9rem;
        }
        
        .success-message {
            color: var(--success);
            padding: 0.7rem;
            background: #90EE90;
            border-radius: 6px;
            margin: 0.8rem 0;
            display: none;
            font-size: 0.9rem;
        }

        /* 响应式调整 */
        @media (max-width: 500px) {
            .header {
                font-size: 1.2rem;
                padding: 1rem;
            }
            
            .card {
                padding: 1rem;
            }
            
            .option-group {
                padding: 0.6rem;
                margin-bottom: 1rem;
            }
            
            label {
                padding: 0.6rem;
            }
            
            .input-field {
                padding: 0.6rem 0.8rem;
                font-size: 0.9rem;
            }
            
            #totalPrice {
                font-size: 1.3rem;
                margin: 1.2rem 0;
            }
            
            .btn {
                padding: 0.9rem;
                font-size: 0.95rem;
            }
            
            .payment-content {
                padding: 1rem;
            }
            
            .payment-method {
                padding: 0.6rem;
                height: 65px;
            }
            
            .payment-method img {
                width: 40px;
                height: 40px;
            }
            
            .payment-method div {
                font-size: 0.8rem;
            }
            
            .qrcode-container {
                min-height: 160px;
            }
            
            .qrcode-image {
                width: 160px;
                height: 160px;
            }
        }
        .sticky-footer {
            position: sticky;
            bottom: 0;
            background: white;
            padding: 0.8rem 0;
            border-top: 1px solid var(--border);
            margin-top: 1rem;
        }