:root {
            --primary-color: #2c3e50;
            --text-color: #333333;
            --text-light: #666666;
            --bg-light: #f8f9fa;
        }

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

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

        /* Header - Sticky and Thin */
        .navbar {
            background-color: #ffffff;
            box-shadow: 0 2px 4px rgba(0,0,0,0.1);
            padding: 0.75rem 0;
            position: sticky;
            top: 0;
            z-index: 1000;
            transition: all 0.3s ease;
        }

        .navbar.scrolled {
            box-shadow: 0 2px 8px rgba(0,0,0,0.15);
        }

        .navbar-brand {
            padding: 0;
        }

        .navbar-brand img {
            height: 40px;
            width: auto;
        }

        .navbar-nav {
            align-items: center;
        }

        .nav-link {
            color: var(--text-color) !important;
            font-weight: 500;
            padding: 0.5rem 1rem !important;
            font-size: 0.95rem;
            transition: color 0.3s ease;
        }

        .nav-link:hover {
            color: var(--primary-color) !important;
        }

        .navbar-toggler {
            border: none;
            padding: 0.25rem 0.5rem;
        }

        .navbar-toggler:focus {
            box-shadow: none;
        }

        /* Banner Slider */
        #bannerCarousel {
            width: 100%;
            max-width: 1440px;
            margin: 0 auto;
            margin-top: 0;
        }

        #bannerCarousel .carousel-inner {
            width: 100%;
            max-width: 1440px;
            margin: 0 auto;
        }

        #bannerCarousel .carousel-item img {
            width: 100%;
            max-width: 1440px;
            height: auto;
            display: block;
            object-fit: cover;
            margin: 0 auto;
        }

        #bannerCarousel .carousel-control-prev,
        #bannerCarousel .carousel-control-next {
            opacity: 0.5;
            transition: opacity 0.3s ease;
        }

        #bannerCarousel .carousel-control-prev:hover,
        #bannerCarousel .carousel-control-next:hover {
            opacity: 1;
        }

        #bannerCarousel .carousel-indicators {
            margin-bottom: 1rem;
        }

        #bannerCarousel .carousel-indicators button {
            width: 10px;
            height: 10px;
            border-radius: 50%;
            background-color: rgba(255,255,255,0.5);
            border: 2px solid rgba(255,255,255,0.8);
        }

        #bannerCarousel .carousel-indicators button.active {
            background-color: rgba(255,255,255,0.9);
        }

        @media (max-width: 768px) {
            #bannerCarousel .carousel-control-prev,
            #bannerCarousel .carousel-control-next {
                opacity: 0.3;
            }
        }

        /* Section 1 - Hero */
        .hero-section {
            padding: 100px 0 80px;
            background-color: #ffffff;
        }

        .hero-content h1 {
            font-size: 3rem;
            font-weight: 700;
            color: var(--text-color);
            margin-bottom: 1.5rem;
            line-height: 1.2;
        }

        .hero-content p {
            font-size: 1.2rem;
            color: var(--text-light);
            margin-bottom: 2.5rem;
        }

        .btn-cta {
            background-color: var(--primary-color);
            color: #ffffff;
            padding: 0.875rem 2rem;
            font-size: 1rem;
            font-weight: 600;
            border-radius: 5px;
            border: none;
            transition: all 0.3s ease;
            text-decoration: none;
            display: inline-block;
        }

        .btn-cta:hover {
            background-color: #1a252f;
            color: #ffffff;
            transform: translateY(-2px);
            box-shadow: 0 4px 12px rgba(0,0,0,0.15);
        }

        .hero-image {
            width: 100%;
            height: auto;
            border-radius: 8px;
        }

        /* Section 2 - What We Measure */
        .section-what-we-measure {
            padding: 80px 0;
            background-color: var(--bg-light);
        }

        .section-what-we-measure h2 {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--text-color);
            margin-bottom: 2rem;
        }

        .section-what-we-measure ul {
            list-style: none;
            padding: 0;
        }

        .section-what-we-measure ul li {
            font-size: 1.1rem;
            color: var(--text-color);
            margin-bottom: 1.25rem;
            padding-left: 1.75rem;
            position: relative;
            line-height: 1.7;
        }

        .section-what-we-measure ul li::before {
            content: "•";
            position: absolute;
            left: 0;
            color: var(--primary-color);
            font-size: 1.5rem;
            font-weight: bold;
        }

        .section-image {
            width: 100%;
            height: auto;
            border-radius: 8px;
        }

        /* Section 3 - How It Works */
        .section-how-it-works {
            padding: 80px 0;
            background-color: #ffffff;
        }

        .section-how-it-works .container {
            max-width: 900px;
        }

        .section-how-it-works h2 {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--text-color);
            margin-bottom: 2rem;
            text-align: center;
        }

        .section-how-it-works .section-image {
            margin-bottom: 2rem;
        }

        .section-how-it-works p {
            font-size: 1.1rem;
            color: var(--text-light);
            text-align: center;
            line-height: 1.8;
        }

        /* Section 4 - Why Biological Aging Rate */
        .section-why-aging {
            padding: 80px 0;
            background-color: var(--bg-light);
        }

        .section-why-aging h2 {
            font-size: 2.5rem;
            font-weight: 700;
            color: var(--text-color);
            margin-bottom: 1.5rem;
            line-height: 1.3;
        }

        /* Footer */
        .footer {
            background-color: var(--primary-color);
            color: #ffffff;
            padding: 2.5rem 0;
            font-size: 0.9rem;
        }

        .footer-top {
            border-bottom: 1px solid rgba(255,255,255,0.2);
            padding-bottom: 1rem;
        }

        .footer-copyright {
            color: #ffffff;
        }

        .footer-links a {
            color: rgba(255,255,255,0.8);
            text-decoration: none;
            transition: color 0.3s ease;
        }

        .footer-links a:hover {
            color: #ffffff;
        }

        .footer-disclaimer {
            font-size: 0.75rem;
            color: rgba(255,255,255,0.7);
            margin-top: 1.5rem;
            margin-bottom: 0;
            line-height: 1.6;
            text-align: center;
        }

        @media (max-width: 767.98px) {
            .footer-disclaimer {
                text-align: left;
                font-size: 0.7rem;
            }

            .footer-top {
                text-align: center;
            }

            .footer-top .col-md-6 {
                text-align: center !important;
            }
        }

        /* Responsive Design - Mobile First Stacking */
        @media (max-width: 991.98px) {
            .hero-content h1 {
                font-size: 2.25rem;
            }

            .hero-content p {
                font-size: 1.1rem;
            }

            .section-what-we-measure h2,
            .section-how-it-works h2,
            .section-why-aging h2 {
                font-size: 2rem;
            }

            .hero-section,
            .section-what-we-measure,
            .section-how-it-works,
            .section-why-aging {
                padding: 60px 0;
            }

            .hero-image,
            .section-image {
                margin-bottom: 2rem;
            }
        }

        @media (max-width: 575.98px) {
            .hero-content h1 {
                font-size: 1.75rem;
            }

            .navbar-brand img {
                height: 32px;
            }

            .section-what-we-measure h2,
            .section-how-it-works h2,
            .section-why-aging h2 {
                font-size: 1.75rem;
            }
        }

        /* Smooth Scroll */
        html {
            scroll-behavior: smooth;
        }