:root {
            --primary-color: #0d6efd;
            --text-dark: #212529;
            --text-gray: #6c757d;
            --bg-light: #f8f9fa;
            --border-color: #dee2e6;
        }

        #product-detail {
            background-color: #fff;
            padding-bottom: 60px;
        }

        .container-custom {
            width: 100%;
            padding-right: 15px;
            padding-left: 15px;
            margin-right: auto;
            margin-left: auto;
            max-width: 1200px;
        }

        /* --- TYPOGRAPHY (Cấu hình chữ) --- */
        
        /* 1. Tên sản phẩm chính (H1) - Mobile mặc định nhỏ */
        h1.title-product {
            font-size: 1.3rem; /* Khoảng 21px */
            font-weight: 800;
            line-height: 1.4;
            color: var(--text-dark);
            margin-bottom: 10px;
            text-transform: capitalize; /* Viết hoa chữ cái đầu */
        }

        /* 2. Tiêu đề các section (Sản phẩm liên quan...) */
        .custom-section-title {
            font-size: 1.25rem;
            font-weight: 700;
            text-transform: uppercase;
            margin-bottom: 1.5rem;
            position: relative;
            display: inline-block;
        }

        /* =========================================
           2. GALLERY ẢNH (VUÔNG - KHÔNG BO GÓC)
           ========================================= */
        .product-images {
            margin-bottom: 30px;
        }

        .gallery-container {
            border: 1px solid var(--border-color);
            background: #fff;
            margin-bottom: 10px;
        }

        .main-slider .swiper-slide {
            width: 100%;
            aspect-ratio: 1 / 1;
            display: flex;
            align-items: center;
            justify-content: center;
            background: #fff;
        }

        .main-slider img {
            max-width: 100%;
            max-height: 100%;
            width: auto;
            height: auto;
            object-fit: contain;
            border-radius: 0 !important;
        }

        /* Thumbnails */
        .gallery-thumbs .swiper-slide {
            aspect-ratio: 1 / 1;
            cursor: pointer;
            border: 1px solid var(--border-color);
            opacity: 0.5;
            transition: 0.3s;
            display: flex;
            align-items: center;
            justify-content: center;
            background: #fff;
        }
        .gallery-thumbs .swiper-slide:hover,
        .gallery-thumbs .swiper-slide-thumb-active {
            opacity: 1;
            border-color: var(--primary-color);
        }
        .gallery-thumbs img {
            max-width: 100%;
            max-height: 100%;
            object-fit: contain;
            border-radius: 0 !important;
        }

        /* =========================================
           3. THÔNG TIN SẢN PHẨM (RIGHT COLUMN)
           ========================================= */
        .details-pro { padding-left: 0; }

        .sku-product {
            font-size: 0.9rem;
            color: var(--text-gray);
            margin-bottom: 20px;
            padding-bottom: 15px;
            border-bottom: 1px solid var(--border-color);
        }

        .description-short {
            font-size: 0.95rem;
            line-height: 1.6;
            color: #444;
            margin-bottom: 25px;
        }

        /* Nút Action */
        .btn-crossover {
            width: 100%;
            padding: 12px 15px;
            font-weight: 700;
            text-transform: uppercase;
            font-size: 0.95rem;
            background: var(--primary-color);
            color: #fff;
            border: none;
            border-radius: 0 !important;
            display: flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
            box-shadow: 0 4px 6px rgba(13, 110, 253, 0.2);
            transition: 0.2s;
        }
        .btn-crossover:hover {
            background-color: #0b5ed7;
            color: #fff;
            transform: translateY(-2px);
            text-decoration: none;
        }

        /* Contact Box */
        .contact-methods {
            display: flex;
            flex-direction: column;
            gap: 15px;
            margin-top: 20px;
        }
        .contact-box {
            display: flex;
            align-items: center;
            padding: 10px 15px;
            border: 1px solid var(--border-color);
            background: #fff;
            color: var(--text-dark);
            text-decoration: none;
            font-weight: 600;
            font-size: 0.95rem;
            transition: 0.3s;
        }
        .contact-box img { margin-right: 15px; width: 30px; height: 30px; }
        .contact-box:hover {
            border-color: var(--primary-color);
            background-color: #f0f7ff;
            color: var(--primary-color);
            text-decoration: none;
        }

        /* =========================================
           4. TABS & NỘI DUNG (QUAN TRỌNG)
           ========================================= */
        .product-tabs { margin-top: 30px; background: #fff; }

        .nav-tabs {
            border-bottom: 2px solid var(--border-color);
            flex-wrap: nowrap; /* Mobile scroll ngang */
            overflow-x: auto;
            white-space: nowrap;
            -webkit-overflow-scrolling: touch;
        }
        .nav-tabs::-webkit-scrollbar { display: none; }

        .nav-tabs .nav-link {
            border: none;
            color: var(--text-gray);
            font-weight: 700;
            font-size: 0.95rem;
            padding: 12px 20px;
            text-transform: uppercase;
            border-bottom: 3px solid transparent;
            border-radius: 0;
        }
        .nav-tabs .nav-link.active {
            color: var(--primary-color);
            background: transparent;
            border-bottom: 3px solid var(--primary-color);
        }

        /* --- CSS NỘI DUNG BÀI VIẾT (CKEDITOR) --- */
        .tab-content { padding: 25px 0; line-height: 1.6; color: #333; }

        /* Ép size các thẻ H trong bài viết nhỏ lại */
        .product-detail-info h1 { font-size: 1.3rem !important; font-weight: 700; margin: 1.5rem 0 1rem; }
        .product-detail-info h2 { font-size: 1.2rem !important; font-weight: 700; margin: 1.5rem 0 1rem; }
        .product-detail-info h3 { font-size: 1.1rem !important; font-weight: 600; margin: 1.2rem 0 0.8rem; }
        .product-detail-info h4 { font-size: 1rem !important; font-weight: 600; }
        .product-detail-info p { margin-bottom: 1rem; text-align: justify; }

        /* Table scroll ngang */
        .product-detail-info table {
            width: 100%; border-collapse: collapse;
            display: block; overflow-x: auto; white-space: nowrap;
            margin-bottom: 1rem;
        }
        .product-detail-info table td, .product-detail-info table th {
            padding: 10px; border: 1px solid var(--border-color);
        }
        
        /* Ảnh trong bài viết */
        .product-detail-info img {
            max-width: 100% !important;
            height: auto !important;
            display: block;
            margin: 10px auto;
        }

        /* =========================================
           5. SẢN PHẨM LIÊN QUAN
           ========================================= */
        .related-product {
            background-color: #f2f4f6;
            padding: 40px 0;
            margin-top: 40px;
        }
        .related-product-slider .swiper-slide { height: auto; display: flex; }
        
        .product-card-wrapper {
            background: #fff; width: 100%;
            border: 1px solid transparent;
            display: flex; flex-direction: column;
            transition: 0.3s;
        }
        .product-card-wrapper:hover {
            box-shadow: 0 10px 20px rgba(0,0,0,0.08);
            transform: translateY(-5px);
        }
        .product-card-wrapper img { border-radius: 0; }
        .product-title { transition: 0.2s; font-size: 0.95rem; font-weight: 600; }
        .product-card-wrapper:hover .product-title { color: var(--primary-color); }

        /* =========================================
           6. RESPONSIVE DESKTOP (MÀN HÌNH LỚN)
           ========================================= */
        @media (min-width: 992px) {
            .details-pro { padding-left: 30px; }
            
            /* Tăng size chữ khi lên máy tính */
            h1.title-product { font-size: 1.8rem; }
            .custom-section-title { font-size: 1.5rem; }
            
            .product-detail-info h1 { font-size: 1.6rem !important; }
            .product-detail-info h2 { font-size: 1.4rem !important; }
            .product-detail-info h3 { font-size: 1.25rem !important; }

            .btn-crossover { width: auto; min-width: 250px; display: inline-flex; }
            .contact-methods { flex-direction: row; }
            
            /* Table bung ra full */
            .product-detail-info table { white-space: normal; display: table; }
        }

        /* Tablet & Mobile (< 992px) */
        @media (max-width: 991.98px) {
            .gallery-thumbs { display: none; }
        }