:root {
            --background: #ffffff; --background-light: #f8f9fa; --foreground: #212529; --muted-foreground: #6c757d;
            --primary-blue: hsl(206, 90%, 54%); --primary-green: hsl(158, 77%, 52%); --card-border: #e9ecef;
            --card-bg: #ffffff; --preheader-bg: #e0f7fa; --footer-bg: #2196f3; --footer-text: #ffffff;
            --shadow-sm: 0 4px 15px rgba(0, 0, 0, 0.05); --shadow-md: 0 8px 30px rgba(0, 0, 0, 0.08);
            --header-shadow: 0 2px 10px rgba(0, 0, 0, 0.08); --radius: 12px; --radius-lg: 16px;
        }
        
        * { margin: 0; padding: 0; box-sizing: border-box; }
        html { scroll-behavior: smooth; }
        body { font-family: 'Inter', sans-serif; background: var(--background-light); color: var(--foreground); line-height: 1.6; }
        .container-large { max-width: 1500px; margin: 0 auto; padding: 0 1.5rem; }
        .btn { padding: 12px 24px; border-radius: 8px; font-weight: 600; text-decoration: none; display: inline-flex; align-items: center; justify-content: center; gap: 8px; border: 1px solid transparent; cursor: pointer; transition: all 0.3s ease; }
        .btn-primary { background: var(--primary-blue); color: white; }
        .btn-primary:hover { transform: translateY(-2px); box-shadow: var(--shadow-md); }
        
        .header { position: sticky; top: 0; z-index: 1000; background: var(--background); box-shadow: var(--header-shadow); }
        .main-nav { padding: 1rem 0; }
        .nav-content { max-width: 1200px; margin: 0 auto; padding: 0 1rem; display: flex; justify-content: space-between; align-items: center; }
        .logo { font-size: 1.75rem; font-weight: 700; color: var(--foreground); text-decoration: none; }
        .nav-menu { display: flex; align-items: center; gap: 2.5rem; list-style: none; }
        .nav-menu a { color: var(--foreground); text-decoration: none; font-weight: 500; }
        .nav-menu a.active, .nav-menu a:hover { color: var(--primary-blue); }

        .page-header { background: white; padding: 3rem 0; text-align: center; border-bottom: 1px solid var(--card-border); }
        .page-header h1 { font-size: 2.8rem; font-weight: 700; color: var(--primary-blue); }
        .page-header p { font-size: 1.1rem; color: var(--muted-foreground); max-width: 700px; margin: 0.5rem auto 0; }

        .filters-section { background: white; padding: 2rem 0; border-bottom: 1px solid var(--card-border); position: sticky; top: 77px; z-index: 900; }
        .filters-form { display: grid; grid-template-columns: 2fr 1fr 1fr 1fr; gap: 1.5rem; align-items: flex-end; }
        .filter-group { display: flex; flex-direction: column; }
        .filter-group label { font-size: 0.875rem; font-weight: 500; margin-bottom: 0.5rem; color: var(--muted-foreground); }
        .filter-group input, .filter-group select { width: 100%; padding: 12px; border-radius: 8px; border: 1px solid var(--card-border); background: var(--background-light); font-size: 1rem; }
        
        .product-grid-section { padding: 4rem 0; }
        .product-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 2rem; }
        #no-results { display: none; text-align: center; padding: 3rem; grid-column: 1 / -1; }

        .product-card { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: var(--radius-lg); overflow: hidden; display: flex; flex-direction: column; box-shadow: var(--shadow-sm); transition: transform 0.3s ease, box-shadow 0.3s ease; }
        .product-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-md); }
        .product-image-wrapper { aspect-ratio: 1 / 1; background-color: var(--background); padding: 1rem; }
        .product-image-wrapper img { width: 100%; height: 100%; object-fit: contain; }
        .product-content { padding: 1.5rem; display: flex; flex-direction: column; flex-grow: 1; }
        .product-name { font-size: 1.25rem; font-weight: 600; margin-bottom: 0.25rem; }
        .pack-details { font-size: 0.875rem; color: var(--muted-foreground); margin-bottom: 1rem; min-height: 20px; }
        .generic-name { font-size: 0.9rem; margin-bottom: 1.5rem; }
        .product-tags { margin-bottom: 1.5rem; display: flex; flex-wrap: wrap; gap: 0.5rem; }
        .tag { font-size: 0.75rem; font-weight: 500; padding: 4px 10px; border-radius: 20px; }
        .tag.dosage { background-color: hsl(206, 100%, 94%); color: hsl(206, 90%, 40%); }
        .tag.category { background-color: hsl(158, 100%, 94%); color: hsl(158, 77%, 40%); }
        .product-card .btn { margin-top: auto; width: 100%; }

        #loading-sentinel { height: 50px; } /* Invisible element for observer */

        .cta-section { background-image: linear-gradient(120deg, var(--primary-blue) 0%, var(--primary-green) 100%); color: white; padding: 4rem 0; text-align: center; }
        .cta-section h2 { font-size: 2.5rem; margin-bottom: 1rem; }
        .cta-section p { max-width: 600px; margin: 0 auto 2rem; opacity: 0.9; }

        .footer { background: var(--footer-bg); color: var(--footer-text); padding: 5rem 0 0; }
        .footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 3rem; }
        .footer-col h4 { font-size: 1.25rem; margin-bottom: 1.5rem; color: white; }
        .footer-col p, .footer-col a { color: var(--footer-text); text-decoration: none; margin-bottom: 0.75rem; display: block; opacity: 0.8; }
        .footer-bottom-bar { border-top: 1px solid rgba(255, 255, 255, 0.2); margin-top: 4rem; padding: 1.5rem 0; text-align: center; font-size: 0.85rem; color: rgba(255, 255, 255, 0.7); }

        @media (max-width: 1200px) { .product-grid { grid-template-columns: repeat(3, 1fr); } }
        @media (max-width: 992px) { .product-grid { grid-template-columns: repeat(2, 1fr); } .filters-form { grid-template-columns: 1fr 1fr; } }
        @media (max-width: 768px) { .filters-form { grid-template-columns: 1fr; } .product-grid { grid-template-columns: 1fr; } .filters-section { top: 65px; } }