:root {
    --color-primary: #2563eb;
    --color-primary-dark: #1e40af;
    --color-primary-light: #3b82f6;
    --color-secondary: #7c3aed;
    --color-accent: #06b6d4;
    
    --color-text-primary: #0f172a;
    --color-text-secondary: #475569;
    --color-text-tertiary: #64748b;
    
    --color-bg-primary: #ffffff;
    --color-bg-secondary: #f8fafc;
    --color-bg-tertiary: #f1f5f9;
    
    --color-border: #e2e8f0;
    --color-border-light: #f1f5f9;
    
    --color-success: #10b981;
    --color-warning: #f59e0b;
    --color-error: #ef4444;
    
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    --shadow-2xl: 0 25px 50px -12px rgb(0 0 0 / 0.25);
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
    
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-display: 'Playfair Display', Georgia, serif;
    
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 350ms cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text-primary);
    background-color: var(--color-bg-primary);
    overflow-x: hidden;
}

.page-wrapper {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* Header */
.header {
    background: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-border);
    padding: 1.5rem 0;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(12px);
    background: rgba(255, 255, 255, 0.9);
}

.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.brand {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.brand-symbol {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    color: white;
    font-weight: 600;
}

.brand-text {
    display: flex;
    flex-direction: column;
}

.brand-title {
    font-family: var(--font-display);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-text-primary);
    line-height: 1.2;
}

.brand-subtitle {
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    font-weight: 400;
}

.built-badge {
    padding: 0.5rem 1rem;
    background: var(--color-bg-tertiary);
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    color: var(--color-text-secondary);
    text-decoration: none;
    transition: all var(--transition-base);
    font-weight: 500;
}

.built-badge:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-1px);
}

/* Navigation */
.navbar {
    background: var(--color-bg-primary);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 81px;
    z-index: 90;
    backdrop-filter: blur(12px);
    background: rgba(255, 255, 255, 0.95);
}

.nav-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0.75rem 0;
}

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

.nav-link {
    color: var(--color-text-secondary);
    text-decoration: none;
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 0.5rem 0;
    position: relative;
    transition: color var(--transition-base);
}

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

.nav-link:hover,
.nav-link.active {
    color: var(--color-primary);
}

.nav-link.active::after {
    width: 100%;
}

.mobile-toggle {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
}

.hamburger {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--color-text-primary);
    position: relative;
    transition: var(--transition-base);
}

.hamburger::before,
.hamburger::after {
    content: '';
    position: absolute;
    width: 24px;
    height: 2px;
    background: var(--color-text-primary);
    transition: var(--transition-base);
}

.hamburger::before {
    top: -7px;
}

.hamburger::after {
    bottom: -7px;
}

/* Main Content */
.main-content {
    flex: 1;
}

/* Hero Section */
.hero-section {
    padding: 5rem 0 6rem;
    background: linear-gradient(180deg, var(--color-bg-secondary) 0%, var(--color-bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

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

.hero-content {
    animation: fadeInUp 0.8s ease-out;
}

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

.hero-badge {
    display: inline-block;
    padding: 0.5rem 1rem;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-secondary));
    color: white;
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    letter-spacing: 0.5px;
}

.hero-title {
    font-family: var(--font-display);
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    color: var(--color-text-primary);
    margin-bottom: 1.5rem;
    letter-spacing: -0.02em;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 2rem;
    max-width: 540px;
}

.hero-actions {
    display: flex;
    gap: 1rem;
    margin-bottom: 3rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    font-family: var(--font-sans);
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    box-shadow: var(--shadow-md);
}

.btn-primary:hover {
    background: var(--color-primary-dark);
    box-shadow: var(--shadow-lg);
    transform: translateY(-2px);
}

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

.btn-secondary:hover {
    border-color: var(--color-primary);
    background: var(--color-bg-secondary);
}

.hero-stats {
    display: flex;
    gap: 3rem;
}

.stat-item {
    display: flex;
    flex-direction: column;
}

.stat-number {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-primary);
    line-height: 1;
    font-family: var(--font-display);
}

.stat-label {
    font-size: 0.875rem;
    color: var(--color-text-tertiary);
    margin-top: 0.25rem;
}

/* Hero Visual */
.hero-visual {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 500px;
}

.visual-container {
    position: relative;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.visual-ring {
    position: absolute;
    border: 2px solid;
    border-radius: 50%;
    opacity: 0.3;
}

.ring-1 {
    width: 300px;
    height: 300px;
    border-color: var(--color-primary);
    animation: rotate 20s linear infinite;
}

.ring-2 {
    width: 400px;
    height: 400px;
    border-color: var(--color-secondary);
    animation: rotate 30s linear infinite reverse;
}

.ring-3 {
    width: 500px;
    height: 500px;
    border-color: var(--color-accent);
    animation: rotate 40s linear infinite;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}

.visual-center {
    width: 200px;
    height: 200px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-2xl);
    z-index: 1;
}

.infinity-symbol {
    font-size: 5rem;
    color: white;
    font-weight: 700;
}

.visual-particles {
    position: absolute;
    width: 100%;
    height: 100%;
}

.particle {
    position: absolute;
    width: 8px;
    height: 8px;
    background: var(--color-primary);
    border-radius: 50%;
    animation: float 3s ease-in-out infinite;
    animation-delay: calc(var(--i) * 0.5s);
}

.particle:nth-child(1) { top: 10%; left: 20%; }
.particle:nth-child(2) { top: 30%; right: 15%; }
.particle:nth-child(3) { bottom: 25%; left: 15%; }
.particle:nth-child(4) { bottom: 15%; right: 25%; }
.particle:nth-child(5) { top: 50%; left: 5%; }
.particle:nth-child(6) { top: 50%; right: 5%; }

@keyframes float {
    0%, 100% {
        transform: translateY(0);
        opacity: 0.7;
    }
    50% {
        transform: translateY(-20px);
        opacity: 1;
    }
}

/* Sections */
.intro-section,
.chapters-preview-section,
.benefits-section,
.cta-section {
    padding: 5rem 0;
}

.section-header {
    text-align: center;
    max-width: 720px;
    margin: 0 auto 3rem;
}

.section-header.centered {
    text-align: center;
}

.section-label {
    display: inline-block;
    padding: 0.375rem 1rem;
    background: var(--color-bg-tertiary);
    color: var(--color-primary);
    border-radius: var(--radius-xl);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.section-title {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: 1rem;
    line-height: 1.2;
}

.section-description {
    font-size: 1.125rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* Feature Grid */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
}

.feature-card {
    padding: 2rem;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    transition: all var(--transition-base);
}

.feature-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-lg);
    transform: translateY(-4px);
}

.feature-icon {
    width: 64px;
    height: 64px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-secondary));
    border-radius: var(--radius-lg);
    margin-bottom: 1.5rem;
    color: white;
}

.feature-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 0.75rem;
}

.feature-text {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

/* Chapters Grid */
.chapters-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 2rem;
    margin-bottom: 3rem;
}

.chapter-card {
    padding: 2rem;
    background: var(--color-bg-primary);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    text-decoration: none;
    transition: all var(--transition-base);
    display: flex;
    flex-direction: column;
}

.chapter-card:hover {
    border-color: var(--color-primary);
    box-shadow: var(--shadow-xl);
    transform: translateY(-4px);
}

.chapter-badge {
    display: inline-block;
    padding: 0.375rem 0.875rem;
    background: var(--color-bg-tertiary);
    color: var(--color-primary);
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 700;
    margin-bottom: 1rem;
    align-self: flex-start;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.chapter-title {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: 0.75rem;
    line-height: 1.3;
}

.chapter-excerpt {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
    flex: 1;
    margin-bottom: 1.5rem;
}

.chapter-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 1rem;
    border-top: 1px solid var(--color-border-light);
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.875rem;
    color: var(--color-text-tertiary);
}

.meta-item svg {
    opacity: 0.7;
}

.chapter-arrow {
    font-size: 1.25rem;
    color: var(--color-primary);
    transition: transform var(--transition-base);
}

.chapter-card:hover .chapter-arrow {
    transform: translateX(4px);
}

.view-all-section {
    text-align: center;
}

.btn-outline-large {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    background: transparent;
    color: var(--color-primary);
    border: 2px solid var(--color-primary);
    border-radius: var(--radius-lg);
    font-weight: 600;
    font-size: 1rem;
    text-decoration: none;
    transition: all var(--transition-base);
}

.btn-outline-large:hover {
    background: var(--color-primary);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

/* Benefits Section */
.benefits-section {
    background: var(--color-bg-secondary);
}

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

.benefits-intro {
    font-size: 1rem;
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-bottom: 2rem;
}

.benefits-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.benefit-item {
    display: flex;
    gap: 1.25rem;
}

.benefit-icon {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--color-primary-light), var(--color-secondary));
    border-radius: var(--radius-lg);
    color: white;
}

.benefit-text h4 {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--color-text-primary);
    margin-bottom: 0.5rem;
}

.benefit-text p {
    font-size: 0.9375rem;
    color: var(--color-text-secondary);
    line-height: 1.6;
}

.benefits-visual {
    display: flex;
    justify-content: center;
}

.visual-stack {
    position: relative;
    width: 400px;
    height: 400px;
}

.stack-card {
    position: absolute;
    width: 280px;
    height: 160px;
    background: white;
    border-radius: var(--radius-xl);
    padding: 2rem;
    box-shadow: var(--shadow-xl);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    transition: transform var(--transition-slow);
}

.stack-card:hover {
    transform: scale(1.05);
}

.card-1 {
    top: 0;
    left: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    z-index: 3;
}

.card-2 {
    top: 80px;
    left: 60px;
    background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
    color: white;
    z-index: 2;
}

.card-3 {
    top: 160px;
    left: 120px;
    background: linear-gradient(135deg, #4facfe 0%, #00f2fe 100%);
    color: white;
    z-index: 1;
}

.card-icon {
    font-size: 3rem;
}

.card-label {
    font-size: 1.25rem;
    font-weight: 600;
}

/* CTA Section */
.cta-section {
    padding: 4rem 0;
}

.cta-card {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-2xl);
    padding: 4rem;
    position: relative;
    overflow: hidden;
}

.cta-content {
    position: relative;
    z-index: 2;
    text-align: center;
    max-width: 640px;
    margin: 0 auto;
}

.cta-title {
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 700;
    color: white;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.cta-text {
    font-size: 1.125rem;
    color: rgba(255, 255, 255, 0.9);
    line-height: 1.7;
    margin-bottom: 2rem;
}

.btn-cta {
    background: white;
    color: var(--color-primary);
    padding: 1rem 2rem;
    font-size: 1.125rem;
    box-shadow: var(--shadow-xl);
}

.btn-cta:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-2xl);
}

.cta-decoration {
    position: absolute;
    top: 0;
    right: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    opacity: 0.1;
}

.decoration-circle {
    position: absolute;
    top: -100px;
    right: -100px;
    width: 400px;
    height: 400px;
    border: 2px solid white;
    border-radius: 50%;
}

/* Footer */
.footer {
    background: var(--color-text-primary);
    color: white;
    padding: 4rem 0 2rem;
    margin-top: auto;
}

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

.footer-brand {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.footer-symbol {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    font-weight: 600;
}

.footer-brand h3 {
    font-size: 1.125rem;
    font-weight: 600;
}

.footer-description {
    font-size: 0.9375rem;
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.6;
}

.footer-heading {
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 1rem;
}

.footer-links {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    font-size: 0.9375rem;
    transition: color var(--transition-base);
}

.footer-links a:hover {
    color: white;
}

.footer-bottom {
    padding-top: 2rem;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.875rem;
    color: rgba(255, 255, 255, 0.6);
}

.footer-bottom a {
    color: rgba(255, 255, 255, 0.8);
    text-decoration: none;
}

.footer-bottom a:hover {
    color: white;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .hero-grid,
    .benefits-grid {
        grid-template-columns: 1fr;
        gap: 3rem;
    }
    
    .hero-visual {
        order: -1;
        height: 400px;
    }
    
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .chapters-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-grid {
        grid-template-columns: 1fr 1fr;
        gap: 2rem;
    }
}

@media (max-width: 768px) {
    .nav-links {
        display: none;
    }
    
    .mobile-toggle {
        display: block;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .feature-grid,
    .chapters-grid {
        grid-template-columns: 1fr;
    }
    
    .hero-stats {
        flex-direction: column;
        gap: 1.5rem;
    }
    
    .footer-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-bottom {
        flex-direction: column;
        gap: 1rem;
        text-align: center;
    }
    
    .cta-card {
        padding: 3rem 2rem;
    }
    
    .cta-title {
        font-size: 2rem;
    }
}

@media (max-width: 480px) {
    .brand-title {
        font-size: 1rem;
    }
    
    .brand-subtitle {
        font-size: 0.75rem;
    }
    
    .hero-title {
        font-size: 2rem;
    }
    
    .hero-actions {
        flex-direction: column;
        width: 100%;
    }
    
    .btn {
        width: 100%;
        justify-content: center;
    }
}