/* ===========================
   RESET & BASE STYLES
   =========================== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Color Palette */
    --color-primary: #D4A574;
    --color-primary-dark: #B8935F;
    --color-secondary: #E8D5C4;
    --color-accent: #C9A881;
    --color-white: #FFFFFF;
    --color-cream: #FAF8F5;
    --color-beige: #F5F0EB;
    --color-text: #2C2417;
    --color-text-light: #6B5D4F;
    --color-border: #E5DDD5;

    /* Typography */
    --font-serif: 'Crimson Pro', serif;
    --font-sans: 'Inter', sans-serif;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 2rem;
    --spacing-lg: 4rem;
    --spacing-xl: 6rem;

    /* Transitions */
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background-color: var(--color-cream);
    line-height: 1.7;
    font-size: 16px;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
}

h1, h2, h3, h4, h5, h6 {
    font-family: var(--font-serif);
    font-weight: 600;
    line-height: 1.3;
    color: var(--color-text);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.25rem; }

a {
    text-decoration: none;
    color: inherit;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* ===========================
   NAVIGATION
   =========================== */
.main-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(250, 248, 245, 0.95);
    backdrop-filter: blur(10px);
    z-index: 1000;
    border-bottom: 1px solid var(--color-border);
    transition: var(--transition-smooth);
}

.main-nav.scrolled {
    box-shadow: 0 2px 20px rgba(44, 36, 23, 0.08);
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 1.2rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-primary-dark);
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 2rem;
    align-items: center;
}

.nav-links a {
    color: var(--color-text-light);
    font-weight: 500;
    font-size: 0.95rem;
    transition: var(--transition-smooth);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    transition: var(--transition-smooth);
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--color-primary-dark);
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.mobile-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 5px;
}

.mobile-toggle span {
    width: 25px;
    height: 2px;
    background: var(--color-text);
    transition: var(--transition-smooth);
}

/* ===========================
   HERO SECTION
   =========================== */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: relative;
    padding: 8rem 2rem 4rem;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #FAF8F5 0%, #F5F0EB 50%, #E8D5C4 100%);
    z-index: 0;
}

.crystal-pattern {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image:
        radial-gradient(circle at 20% 50%, rgba(212, 165, 116, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(232, 213, 196, 0.15) 0%, transparent 50%),
        radial-gradient(circle at 40% 20%, rgba(201, 168, 129, 0.08) 0%, transparent 50%);
    animation: crystalFloat 20s ease-in-out infinite;
}

@keyframes crystalFloat {
    0%, 100% { transform: translate(0, 0) scale(1); }
    50% { transform: translate(-10px, -10px) scale(1.05); }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 800px;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    color: var(--color-primary-dark);
    animation: fadeInUp 0.8s ease-out;
}

.hero-subtitle {
    font-size: 1.5rem;
    color: var(--color-text-light);
    margin-bottom: 2rem;
    font-family: var(--font-serif);
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-description {
    font-size: 1.1rem;
    color: var(--color-text-light);
    line-height: 1.8;
    margin-bottom: 3rem;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.hero-buttons {
    display: flex;
    gap: 1.5rem;
    justify-content: center;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.btn {
    padding: 1rem 2.5rem;
    border-radius: 50px;
    font-weight: 500;
    font-size: 1rem;
    transition: var(--transition-smooth);
    display: inline-block;
}

.btn-primary {
    background: var(--color-primary);
    color: var(--color-white);
    border: 2px solid var(--color-primary);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(212, 165, 116, 0.3);
}

.btn-secondary {
    background: transparent;
    color: var(--color-primary-dark);
    border: 2px solid var(--color-primary);
}

.btn-secondary:hover {
    background: var(--color-primary);
    color: var(--color-white);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(212, 165, 116, 0.2);
}

.scroll-indicator {
    position: absolute;
    bottom: 3rem;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    color: var(--color-text-light);
    font-size: 0.85rem;
    animation: fadeInUp 0.8s ease-out 0.8s both;
}

.scroll-arrow {
    width: 24px;
    height: 24px;
    border-left: 2px solid var(--color-primary);
    border-bottom: 2px solid var(--color-primary);
    transform: rotate(-45deg);
    margin: 0.5rem auto 0;
    animation: bounce 2s infinite;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bounce {
    0%, 100% { transform: translateY(0) rotate(-45deg); }
    50% { transform: translateY(-10px) rotate(-45deg); }
}

/* ===========================
   INTRO SECTION
   =========================== */
.intro-section {
    padding: var(--spacing-xl) 0;
    background: var(--color-white);
}

.intro-section h2 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-dark);
}

.intro-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2.5rem;
    margin-top: 3rem;
}

.intro-card {
    text-align: center;
    padding: 2.5rem 2rem;
    background: var(--color-beige);
    border-radius: 16px;
    transition: var(--transition-smooth);
}

.intro-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 15px 40px rgba(212, 165, 116, 0.15);
}

.intro-icon {
    font-size: 3rem;
    margin-bottom: 1.5rem;
}

.intro-card h3 {
    margin-bottom: 1rem;
    color: var(--color-text);
}

.intro-card p {
    color: var(--color-text-light);
    line-height: 1.7;
}

/* ===========================
   FEATURE SECTIONS
   =========================== */
.feature-section {
    padding: var(--spacing-xl) 0;
}

.feature-section.alt {
    background: var(--color-beige);
}

.feature-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 4rem;
    align-items: center;
}

.feature-content.reverse {
    direction: rtl;
}

.feature-content.reverse > * {
    direction: ltr;
}

.feature-text h2 {
    margin-bottom: 1.5rem;
    color: var(--color-primary-dark);
}

.feature-text p {
    margin-bottom: 1.5rem;
    color: var(--color-text-light);
    font-size: 1.05rem;
}

.text-link {
    color: var(--color-primary-dark);
    font-weight: 500;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition-smooth);
}

.text-link:hover {
    color: var(--color-primary);
    transform: translateX(5px);
}

.timeline-preview {
    background: var(--color-white);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(44, 36, 23, 0.08);
}

.timeline-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 0;
    border-bottom: 1px solid var(--color-border);
}

.timeline-item:last-child {
    border-bottom: none;
}

.timeline-item .year {
    font-family: var(--font-serif);
    font-weight: 600;
    font-size: 1.3rem;
    color: var(--color-primary);
}

.timeline-item .event {
    color: var(--color-text-light);
}

.molecule-diagram {
    background: var(--color-white);
    padding: 3rem;
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(44, 36, 23, 0.08);
    text-align: center;
}

.molecule-structure {
    position: relative;
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin-bottom: 2rem;
}

.atom {
    width: 100px;
    height: 100px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    color: var(--color-white);
    font-size: 0.9rem;
}

.atom.glucose {
    background: linear-gradient(135deg, #D4A574, #B8935F);
}

.atom.fructose {
    background: linear-gradient(135deg, #E8D5C4, #D4A574);
}

.connection {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 80px;
    height: 3px;
    background: var(--color-primary);
}

.diagram-label {
    font-family: var(--font-serif);
    font-size: 1.2rem;
    color: var(--color-text-light);
}

/* ===========================
   QUICK LINKS
   =========================== */
.quick-links {
    padding: var(--spacing-xl) 0;
    background: var(--color-white);
}

.quick-links h2 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
    color: var(--color-primary-dark);
}

.topics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 2rem;
}

.topic-card {
    padding: 2.5rem 2rem;
    background: var(--color-beige);
    border-radius: 16px;
    border: 2px solid transparent;
    transition: var(--transition-smooth);
}

.topic-card:hover {
    border-color: var(--color-primary);
    transform: translateY(-5px);
    box-shadow: 0 15px 35px rgba(212, 165, 116, 0.2);
}

.topic-card h3 {
    margin-bottom: 1rem;
    color: var(--color-text);
}

.topic-card p {
    color: var(--color-text-light);
}

/* ===========================
   FOOTER
   =========================== */
.main-footer {
    background: var(--color-text);
    color: var(--color-secondary);
    padding: var(--spacing-lg) 0 var(--spacing-md);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 3rem;
    margin-bottom: 3rem;
}

.footer-brand h3 {
    color: var(--color-primary);
    margin-bottom: 1rem;
}

.footer-brand p {
    line-height: 1.8;
    color: var(--color-secondary);
}

.footer-links h4 {
    color: var(--color-white);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.footer-links ul {
    list-style: none;
}

.footer-links a {
    color: var(--color-secondary);
    display: block;
    padding: 0.4rem 0;
    transition: var(--transition-smooth);
}

.footer-links a:hover {
    color: var(--color-primary);
    transform: translateX(5px);
}

.footer-bottom {
    border-top: 1px solid rgba(232, 213, 196, 0.2);
    padding-top: 2rem;
    text-align: center;
}

.disclaimer {
    color: var(--color-secondary);
    font-size: 0.9rem;
    margin-bottom: 1rem;
    line-height: 1.7;
}

.copyright {
    color: var(--color-text-light);
    font-size: 0.85rem;
}

/* ===========================
   RESPONSIVE DESIGN
   =========================== */
@media (max-width: 968px) {
    .nav-links {
        position: fixed;
        top: 73px;
        left: -100%;
        flex-direction: column;
        background: var(--color-white);
        width: 100%;
        padding: 2rem;
        box-shadow: 0 10px 30px rgba(44, 36, 23, 0.1);
        transition: var(--transition-smooth);
        align-items: flex-start;
    }

    .nav-links.active {
        left: 0;
    }

    .mobile-toggle {
        display: flex;
    }

    .mobile-toggle.active span:nth-child(1) {
        transform: rotate(45deg) translate(7px, 7px);
    }

    .mobile-toggle.active span:nth-child(2) {
        opacity: 0;
    }

    .mobile-toggle.active span:nth-child(3) {
        transform: rotate(-45deg) translate(6px, -6px);
    }

    .feature-content,
    .feature-content.reverse {
        grid-template-columns: 1fr;
        direction: ltr;
        gap: 3rem;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    h1 { font-size: 2.5rem; }
    h2 { font-size: 2rem; }

    .hero {
        padding: 6rem 1.5rem 3rem;
        min-height: 90vh;
    }

    .hero-title {
        font-size: 3rem;
    }

    .hero-subtitle {
        font-size: 1.2rem;
    }

    .hero-buttons {
        flex-direction: column;
        gap: 1rem;
    }

    .btn {
        width: 100%;
        text-align: center;
    }

    .intro-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .molecule-structure {
        gap: 1.5rem;
    }

    .atom {
        width: 80px;
        height: 80px;
        font-size: 0.8rem;
    }

    .connection {
        width: 60px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 1.5rem;
    }

    .hero-title {
        font-size: 2.5rem;
    }

    .nav-container {
        padding: 1rem 1.5rem;
    }

    .molecule-structure {
        flex-direction: column;
        align-items: center;
        gap: 2rem;
    }

    .connection {
        width: 3px;
        height: 60px;
        top: 40%;
    }
}