:root {
                --primary: #2563eb;
                --primary-dark: #1d4ed8;
                --text: #1a1a1a;
                --text-muted: #6b7280;
                --bg: #ffffff;
                --bg-alt: #f9fafb;
                --border: #e5e7eb;
                --success: #10b981;
                --error: #ef4444;
            }

            * { box-sizing: border-box; margin: 0; padding: 0; }

            body {
                font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
                line-height: 1.6;
                color: var(--text);
                background: var(--bg);
            }

            .container { max-width: 1200px; margin: 0 auto; padding: 0 20px; }

            /* Header */
            header {
                background: var(--bg);
                border-bottom: 1px solid var(--border);
                padding: 16px 0;
                position: sticky;
                top: 0;
                z-index: 100;
            }

            header .container {
                display: flex;
                justify-content: space-between;
                align-items: center;
            }

            .logo { font-size: 24px; font-weight: 700; color: var(--primary); text-decoration: none; }

            nav a {
                margin-left: 24px;
                color: var(--text);
                text-decoration: none;
                transition: color 0.2s;
            }

            nav a:hover { color: var(--primary); }

            /* Product Grid */
            .products-grid {
                display: grid;
                grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
                gap: 24px;
                padding: 40px 0;
            }

            .product-card {
                background: var(--bg);
                border: 1px solid var(--border);
                border-radius: 12px;
                overflow: hidden;
                transition: transform 0.2s, box-shadow 0.2s;
            }

            .product-card:hover {
                transform: translateY(-4px);
                box-shadow: 0 12px 24px rgba(0,0,0,0.1);
            }

            .product-card img {
                width: 100%;
                height: 200px;
                object-fit: cover;
            }

            .product-card-body { padding: 16px; }
            .product-card h3 { font-size: 16px; margin-bottom: 8px; }
            .product-card .price { font-size: 18px; font-weight: 700; color: var(--primary); }
            .product-card .price del { color: var(--text-muted); font-weight: 400; margin-right: 8px; }

            /* Product Detail */
            .product-detail {
                display: grid;
                grid-template-columns: 1fr 1fr;
                gap: 48px;
                padding: 48px 0;
            }

            /* Image Gallery */
            .product-gallery { position: relative; }
            .gallery-main { margin-bottom: 16px; }
            .gallery-main img { width: 100%; border-radius: 12px; aspect-ratio: 1; object-fit: cover; }
            .gallery-thumbnails { display: flex; gap: 12px; overflow-x: auto; padding-bottom: 8px; }
            .gallery-thumb { width: 80px; height: 80px; object-fit: cover; border-radius: 8px; cursor: pointer; border: 2px solid transparent; opacity: 0.6; transition: all 0.2s; }
            .gallery-thumb:hover { opacity: 1; }
            .gallery-thumb.active { border-color: var(--primary); opacity: 1; }

            .product-info h1 { font-size: 32px; margin-bottom: 16px; }
            .product-info .price { font-size: 28px; font-weight: 700; color: var(--primary); margin-bottom: 24px; }
            .product-info .description { color: var(--text-muted); margin-bottom: 24px; }

            /* Quantity Selector */
            .quantity-selector { display: flex; align-items: center; gap: 12px; margin-bottom: 24px; }
            .quantity-selector label { font-weight: 500; }
            .qty-btn { width: 36px; height: 36px; border: 1px solid var(--border); background: var(--bg); border-radius: 8px; font-size: 18px; cursor: pointer; transition: all 0.2s; }
            .qty-btn:hover { background: var(--bg-alt); border-color: var(--primary); }
            .quantity-selector input { width: 60px; height: 36px; text-align: center; border: 1px solid var(--border); border-radius: 8px; font-size: 16px; }

            .btn {
                display: inline-block;
                padding: 14px 28px;
                background: var(--primary);
                color: white;
                border: none;
                border-radius: 8px;
                font-size: 16px;
                font-weight: 600;
                cursor: pointer;
                text-decoration: none;
                transition: background 0.2s;
            }
            .btn:hover { background: var(--primary-dark); }
            .btn-large { width: 100%; padding: 18px; font-size: 18px; }
            .btn-secondary { background: var(--bg-alt); color: var(--text); border: 1px solid var(--border); }
            .btn-secondary:hover { background: var(--border); }
            .btn-danger { background: var(--error); }
            .btn-danger:hover { background: #dc2626; }

            /* Cart Page */
            .cart-page { padding: 48px 0; }
            .cart-page h1 { font-size: 32px; margin-bottom: 32px; }
            .cart-empty { text-align: center; padding: 60px 20px; color: var(--text-muted); }
            .cart-empty h2 { margin-bottom: 16px; color: var(--text); }
            .cart-items { margin-bottom: 32px; }
            .cart-item { display: grid; grid-template-columns: 100px 1fr auto auto; gap: 20px; align-items: center; padding: 20px; border: 1px solid var(--border); border-radius: 12px; margin-bottom: 16px; }
            .cart-item img { width: 100px; height: 100px; object-fit: cover; border-radius: 8px; }
            .cart-item-info h3 { font-size: 18px; margin-bottom: 4px; }
            .cart-item-info .price { color: var(--primary); font-weight: 600; }
            .cart-item-qty { display: flex; align-items: center; gap: 8px; }
            .cart-item-qty button { width: 32px; height: 32px; border: 1px solid var(--border); background: var(--bg); border-radius: 6px; cursor: pointer; }
            .cart-item-qty span { width: 40px; text-align: center; font-weight: 500; }
            .cart-item-total { font-size: 18px; font-weight: 700; min-width: 100px; text-align: right; }
            .cart-item-remove { color: var(--error); cursor: pointer; padding: 8px; }

            /* Cart Summary */
            .cart-summary { background: var(--bg-alt); border-radius: 12px; padding: 24px; max-width: 400px; margin-left: auto; }
            .cart-summary h3 { font-size: 20px; margin-bottom: 20px; }
            .summary-row { display: flex; justify-content: space-between; padding: 12px 0; border-bottom: 1px solid var(--border); }
            .summary-row:last-of-type { border-bottom: none; }
            .summary-row.total { font-size: 20px; font-weight: 700; margin-top: 12px; padding-top: 16px; border-top: 2px solid var(--border); }

            /* Checkout Page */
            .checkout-page { padding: 48px 0; }
            .checkout-grid { display: grid; grid-template-columns: 1fr 400px; gap: 48px; }
            .checkout-form h2 { font-size: 24px; margin-bottom: 24px; }
            .form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
            .form-group { margin-bottom: 20px; }
            .form-group label { display: block; font-weight: 500; margin-bottom: 8px; }
            .form-group input, .form-group select { width: 100%; padding: 12px; border: 1px solid var(--border); border-radius: 8px; font-size: 16px; }
            .form-group input:focus, .form-group select:focus { outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1); }
            #card-element { padding: 14px; border: 1px solid var(--border); border-radius: 8px; background: white; }
            .order-summary { background: var(--bg-alt); border-radius: 12px; padding: 24px; position: sticky; top: 100px; }
            .order-items { max-height: 300px; overflow-y: auto; margin-bottom: 20px; }
            .order-item { display: flex; gap: 12px; padding: 12px 0; border-bottom: 1px solid var(--border); }
            .order-item img { width: 60px; height: 60px; object-fit: cover; border-radius: 6px; }
            .order-item-details { flex: 1; }
            .order-item-name { font-weight: 500; }
            .order-item-qty { color: var(--text-muted); font-size: 14px; }
            .order-item-price { font-weight: 600; }

            /* Alerts */
            .alert { padding: 16px; border-radius: 8px; margin-bottom: 20px; }
            .alert-error { background: #fef2f2; color: var(--error); border: 1px solid #fecaca; }
            .alert-success { background: #f0fdf4; color: var(--success); border: 1px solid #bbf7d0; }

            /* Footer */
            footer {
                background: var(--bg-alt);
                border-top: 1px solid var(--border);
                padding: 40px 0;
                margin-top: 60px;
                text-align: center;
                color: var(--text-muted);
            }

            /* Hero */
            .hero {
                background: linear-gradient(135deg, var(--primary), var(--primary-dark));
                color: white;
                padding: 80px 0;
                text-align: center;
            }
            .hero h1 { font-size: 48px; margin-bottom: 16px; }
            .hero p { font-size: 20px; opacity: 0.9; }

            /* Responsive */
            @media (max-width: 768px) {
                .product-detail { grid-template-columns: 1fr; gap: 24px; }
                .hero h1 { font-size: 32px; }
                .product-info h1 { font-size: 24px; }
                .cart-item { grid-template-columns: 80px 1fr; }
                .cart-item-total { grid-column: 2; text-align: left; }
                .checkout-grid { grid-template-columns: 1fr; }
                .form-row { grid-template-columns: 1fr; }
            }