:root {
            --primary-color: #005f73;
            --secondary-color: #0a9396;
            --accent-color: #94d2bd;
            --text-color: #333;
            --bg-color: #f8f9fa;
            --white: #ffffff;
            --light-gray: #e9ecef;
        }
        body {
            font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
            margin: 0;
            padding: 0;
            background-color: var(--bg-color);
            color: var(--text-color);
            line-height: 1.6;
            scroll-behavior: smooth;
        }
       .container {
            width: 90%;
            max-width: 1200px;
            margin: 0 auto;
            padding: 30px;
        }
        /* Header & Navigation */
        header {
            background-color: var(--white);
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            position: sticky;
            top: 0;
            z-index: 1000;
        }
        nav {
            display: flex;
            justify-content: flex-end;
            align-items: center;
            padding: 1rem 5%;
        }
       .nav-links {
            list-style: none;
            display: flex;
            gap: 25px;
            margin: 0;
            padding: 0;
        }
       .nav-links a {
            text-decoration: none;
            color: var(--primary-color);
            font-weight: 500;
            transition: color 0.3s ease;
        }
       .nav-links a:hover {
            color: var(--secondary-color);
        }
        .hamburger-menu {
            display: none;
            cursor: pointer;
            background: none;
            border: none;
            padding: 0;
            z-index: 1010;
        }
        .hamburger-menu span {
            display: block;
            width: 25px;
            height: 3px;
            background-color: var(--primary-color);
            margin: 5px 0;
            transition: all 0.3s ease-in-out;
        }
        picture { display: contents; }
        .hero-eyebrow {
            text-transform: uppercase;
            letter-spacing: 2px;
            font-size: 0.9rem;
            font-weight: 600;
            color: var(--accent-color);
            margin: 0 0 0.5rem 0;
        }
        /* Hero Section */
       .hero {
            background: linear-gradient(rgba(0, 95, 115, 0.7), rgba(0, 95, 115, 0.7)), url('ceramide-illustration.jpg') no-repeat center center/cover;
            color: var(--white);
            text-align: center;
            padding: 100px 20px;
        }
       .hero h1 {
            font-size: 3rem;
            margin-bottom: 1rem;
        }
       .hero p {
            font-size: 1.2rem;
            max-width: 700px;
            margin: 0 auto 2rem auto;
        }
       .cta-button {
            background-color: var(--accent-color);
            color: var(--primary-color);
            padding: 12px 25px;
            border: none;
            border-radius: 5px;
            text-decoration: none;
            font-weight: bold;
            transition: background-color 0.3s ease;
        }
       .cta-button:hover {
            background-color: #7ac7b1;
        }
        /* General Section Styling */
        section {
            padding: 60px 0;
        }
       .section-title {
            text-align: center;
            font-size: 2.5rem;
            color: var(--primary-color);
            margin-bottom: 40px;
        }
        .subsection-title {
            text-align: center;
            color: var(--primary-color);
            font-size: 1.8rem;
            margin-top: 40px;
            margin-bottom: 20px;
        }
       .grid {
            display: grid;
            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
            gap: 30px;
        }
       .card {
            background-color: var(--white);
            border-radius: 8px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.05);
            padding: 25px;
            text-align: center;
        }
       .card h3 {
            color: var(--secondary-color);
            margin-top: 0;
        }
        .citation-link {
            color: var(--secondary-color);
            text-decoration: none;
            font-weight: 500;
            vertical-align: super;
            font-size: 0.75em;
            line-height: 1;
        }
        .citation-link:hover {
            text-decoration: underline;
        }
        /* Science Section */
        #science .grid {
            grid-template-columns: 1fr 1fr;
            align-items: center;
        }
        #science img {
            max-width: 100%;
            border-radius: 8px;
        }
        /* Visual Gallery Section */
       .visual-gallery {
            display: flex;
            flex-direction: column;
            gap: 40px;
            align-items: center;
            max-width: 800px;
            margin: 0 auto;
        }
       .visual-gallery img {
            width: 100%;
            height: auto;
            border-radius: 8px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
        }
        /* Skin & Hair Sections */
       .benefit-card {
            text-align: left;
            padding: 20px;
        }
       .benefit-card h3 {
            display: flex;
            align-items: center;
            gap: 10px;
        }
       .icon {
            color: var(--secondary-color);
            font-size: 1.5rem;
        }
        /* Products Section */
        #products {
            background-color: var(--light-gray);
        }
       .product-card {
            background: var(--white);
            border-radius: 8px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.1);
            overflow: hidden;
            text-align: center;
        }
       .product-card img {
            width: 100%;
            height: 200px;
            object-fit: cover;
        }
       .product-info {
            padding: 20px;
        }
       .product-info h4 {
            margin: 0 0 10px 0;
            color: var(--primary-color);
        }
       .product-info p {
            font-size: 0.9rem;
            margin-bottom: 15px;
        }
        /* Brands Section */
        #brands .brand-container {
            margin-bottom: 50px;
        }
        #brands .brand-table-wrapper {
            overflow-x: auto;
            margin-bottom: 30px;
        }
        #brands table.brand-table {
            width: 100%;
            border-collapse: collapse;
            background: var(--white);
            box-shadow: 0 4px 8px rgba(0,0,0,0.05);
        }
        #brands .brand-table th, #brands .brand-table td {
            padding: 12px 15px;
            border: 1px solid var(--light-gray);
            text-align: left;
            font-size: 0.9rem;
            vertical-align: middle;
        }
        #brands .brand-table th {
            background-color: var(--primary-color);
            color: var(--white);
            font-weight: bold;
        }
        #brands .brand-table tr:nth-child(even) {
            background-color: var(--bg-color);
        }
        #brands .brand-table a {
            color: var(--primary-color);
            font-weight: bold;
            text-decoration: none;
        }
        #brands .brand-table a:hover {
            color: var(--secondary-color);
            text-decoration: underline;
        }
        #brands .brand-summary {
            background: var(--white);
            padding: 25px;
            border-radius: 8px;
            box-shadow: 0 4px 8px rgba(0,0,0,0.05);
        }
        #brands .brand-summary h4 {
            color: var(--secondary-color);
            margin-top: 0;
            font-size: 1.25rem;
        }
        /* Future Trends Section */
        #trends {
            background-color: var(--light-gray);
        }
        #trends .card h3 {
            font-size: 1.3rem;
        }
        /* FAQ Section */
       .faq-item {
            background: var(--white);
            margin-bottom: 10px;
            border-radius: 5px;
            box-shadow: 0 2px 4px rgba(0,0,0,0.05);
        }
       .faq-item summary {
            padding: 15px;
            font-weight: bold;
            cursor: pointer;
            list-style: none; /* Remove default marker */
            display: flex;
            justify-content: space-between;
            align-items: center;
            color: var(--primary-color);
        }
       .faq-item summary::-webkit-details-marker {
            display: none; /* Chrome */
        }
       .faq-item summary::after {
            content: '+';
            font-size: 1.5rem;
            transition: transform 0.2s;
        }
       .faq-item[open] summary::after {
            transform: rotate(45deg);
        }
       .faq-answer {
            padding: 0 15px 15px;
            border-top: 1px solid var(--light-gray);
        }
        /* Footer */
        footer {
            background-color: var(--primary-color);
            color: var(--white);
            text-align: center;
            padding: 30px 20px;
        }
        footer p {
            margin: 0;
        }
        /* Responsive */
        @media (max-width: 768px) {
           .hamburger-menu {
                display: block;
           }
           .nav-links {
                position: fixed;
                top: 0;
                right: -100%;
                width: 70%;
                max-width: 300px;
                height: 100vh;
                background-color: var(--white);
                box-shadow: -2px 0 5px rgba(0,0,0,0.1);
                flex-direction: column;
                justify-content: center;
                align-items: center;
                transition: right 0.4s ease-in-out;
                gap: 40px;
            }
            .nav-links.nav-active {
                right: 0;
            }
            .hamburger-menu.active span:nth-child(1) {
                transform: translateY(8px) rotate(45deg);
            }
            .hamburger-menu.active span:nth-child(2) {
                opacity: 0;
            }
            .hamburger-menu.active span:nth-child(3) {
                transform: translateY(-8px) rotate(-45deg);
            }
           .hero h1 {
                font-size: 2.5rem;
            }
            #science .grid {
                grid-template-columns: 1fr;
            }
            /* Responsive Table Styles */
            #brands .brand-table thead {
                display: none;
            }
            #brands .brand-table tr {
                display: block;
                margin-bottom: 1em;
                border: 1px solid var(--light-gray);
                border-radius: 8px;
                box-shadow: 0 2px 4px rgba(0,0,0,0.1);
                background: var(--white);
            }
             #brands .brand-table td {
                display: block;
                text-align: right;
                border-bottom: 1px dotted var(--light-gray);
                padding: 10px;
                border-top: none; 
                border-left: none; 
                border-right: none;
            }
             #brands .brand-table td[data-label="Brand"] {
                font-size: 1.1em;
                font-weight: bold;
                background-color: var(--light-gray);
                border-top-left-radius: 7px;
                border-top-right-radius: 7px;
             }
             #brands .brand-table td::before {
                content: attr(data-label);
                float: left;
                font-weight: bold;
                text-transform: uppercase;
                color: var(--primary-color);
            }
             #brands .brand-table td:last-child {
                border-bottom: 0;
            }
        }
    
        /* ---- Multi-page additions ---- */
        .page-hero {
            background: linear-gradient(rgba(0,95,115,0.93), rgba(10,147,150,0.93));
            color: var(--white);
            text-align: center;
            padding: 70px 20px 60px;
        }
        .page-hero h1 { font-size: 2.6rem; margin: 0 0 0.6rem; }
        .page-hero p { max-width: 720px; margin: 0 auto; font-size: 1.15rem; opacity: 0.95; }
        .breadcrumb {
            width: 90%; max-width: 1200px; margin: 0 auto; padding: 16px 30px 0;
            font-size: 0.85rem; color: #6c757d;
        }
        .breadcrumb a { color: var(--primary-color); text-decoration: none; }
        .breadcrumb a:hover { text-decoration: underline; }
        .nav-links a[aria-current="page"] { color: var(--secondary-color); }
        .nav-links a[aria-current="page"]::after {
            content: ''; display: block; height: 2px; background: var(--secondary-color); margin-top: 2px;
        }
        a.card { text-decoration: none; color: inherit; display: block;
            transition: transform 0.2s ease, box-shadow 0.2s ease; }
        a.card:hover { transform: translateY(-4px); box-shadow: 0 10px 24px rgba(0,0,0,0.10); }
        .card-link { display: inline-block; margin-top: 12px; color: var(--secondary-color); font-weight: 600; }
        #related { background-color: var(--light-gray); }