/* ============================================
   Manhattan Co-Simulation Website Styles
   World-Class Professional Design
   ============================================ */

/* ============================================
   CSS Variables & Theme
   ============================================ */
:root {
    /* Colors */
    --primary-color: #3b82f6;
    --primary-dark: #2563eb;
    --primary-light: #60a5fa;
    --secondary-color: #8b5cf6;
    --accent-color: #10b981;
    --danger-color: #ef4444;

    /* Gradients */
    --gradient-primary: linear-gradient(135deg, #3b82f6 0%, #8b5cf6 100%);
    --gradient-power: linear-gradient(135deg, #f59e0b 0%, #ef4444 100%);
    --gradient-traffic: linear-gradient(135deg, #10b981 0%, #3b82f6 100%);
    --gradient-v2g: linear-gradient(135deg, #8b5cf6 0%, #ec4899 100%);

    /* Neutral Colors */
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --bg-dark: #0f172a;
    --bg-card: #ffffff;
    --text-primary: #1e293b;
    --text-secondary: #64748b;
    --text-light: #94a3b8;
    --border-color: #e2e8f0;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;
    --spacing-3xl: 6rem;

    /* Typography */
    --font-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-mono: 'JetBrains Mono', 'Courier New', monospace;

    /* Transitions */
    --transition-fast: 150ms ease;
    --transition-base: 250ms ease;
    --transition-slow: 350ms ease;

    /* Shadows */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);

    /* Border Radius */
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    --radius-2xl: 1.5rem;
}

/* ============================================
   Reset & Base Styles
   ============================================ */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    font-size: 16px;
}

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

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

section {
    padding: var(--spacing-3xl) 0;
}

/* ============================================
   Typography
   ============================================ */
h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

h1 { font-size: 3.5rem; }
h2 { font-size: 2.5rem; }
h3 { font-size: 1.875rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

p {
    margin-bottom: var(--spacing-md);
    color: var(--text-secondary);
}

code {
    font-family: var(--font-mono);
    background: var(--bg-secondary);
    padding: 0.25rem 0.5rem;
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    color: var(--text-primary);
}

.section-dark code {
    background: rgba(255, 255, 255, 0.1);
    color: white;
}

/* ============================================
   Navigation
   ============================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    box-shadow: var(--shadow-sm);
    z-index: 1000;
    transition: all var(--transition-base);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
    background: rgba(255, 255, 255, 0.98);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: var(--spacing-md) var(--spacing-lg);
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--text-primary);
}

.nav-brand i {
    color: var(--primary-color);
    font-size: 1.5rem;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-link {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color var(--transition-fast);
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

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

.nav-link.github-link {
    background: var(--bg-dark);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    transition: all var(--transition-base);
}

.nav-link.github-link:hover {
    background: var(--text-primary);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 4px;
    cursor: pointer;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition-base);
}

/* ============================================
   Hero Section
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding-top: 80px;
}

.hero-background {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    opacity: 0.05;
    z-index: -1;
}

.hero-background::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(circle at 20% 50%, rgba(59, 130, 246, 0.1) 0%, transparent 50%),
        radial-gradient(circle at 80% 80%, rgba(139, 92, 246, 0.1) 0%, transparent 50%);
}

.hero-content {
    text-align: center;
    z-index: 1;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    background: var(--gradient-primary);
    color: white;
    padding: 0.5rem 1.25rem;
    border-radius: 2rem;
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    animation: slideDown 0.6s ease;
}

.hero-title {
    font-size: 4rem;
    font-weight: 800;
    margin-bottom: var(--spacing-md);
    animation: slideUp 0.6s ease 0.2s backwards;
}

.gradient-text {
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-secondary);
    max-width: 800px;
    margin: 0 auto var(--spacing-xl);
    animation: slideUp 0.6s ease 0.4s backwards;
}

.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--spacing-lg);
    max-width: 900px;
    margin: 0 auto var(--spacing-xl);
    animation: slideUp 0.6s ease 0.6s backwards;
}

.stat {
    text-align: center;
    padding: var(--spacing-md);
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.stat:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.stat-value {
    font-size: 2rem;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 0.25rem;
}

.stat-label {
    font-size: 0.875rem;
    color: var(--text-secondary);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    margin-bottom: var(--spacing-xl);
    animation: slideUp 0.6s ease 0.8s backwards;
}

.scroll-indicator {
    font-size: 1.5rem;
    color: var(--primary-color);
    animation: bounce 2s infinite;
    margin-top: var(--spacing-lg);
}

/* ============================================
   Buttons
   ============================================ */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 1.75rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition-base);
    cursor: pointer;
    border: none;
    font-size: 1rem;
}

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

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

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

.btn-secondary:hover {
    border-color: var(--primary-color);
    color: var(--primary-color);
    transform: translateY(-2px);
}

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

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

.section-dark .btn-outline {
    background: transparent;
    color: white;
    border: 2px solid rgba(255, 255, 255, 0.3);
}

.section-dark .btn-outline:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: var(--primary-light);
    color: white;
}

/* ============================================
   Section Styles
   ============================================ */
.section {
    background: var(--bg-primary);
}

.section-dark {
    background: var(--bg-dark);
    color: white;
}

.section-header {
    text-align: center;
    max-width: 800px;
    margin: 0 auto var(--spacing-2xl);
}

.section-title {
    margin-bottom: var(--spacing-md);
}

.section-dark .section-title {
    color: white;
}

.section-dark .section-subtitle {
    color: rgba(255, 255, 255, 0.8);
}

.section-subtitle {
    font-size: 1.125rem;
    color: var(--text-secondary);
}

/* ============================================
   Overview Section
   ============================================ */
.overview-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

.overview-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.overview-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.overview-icon {
    width: 60px;
    height: 60px;
    background: var(--gradient-primary);
    color: white;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.75rem;
    margin-bottom: var(--spacing-md);
}

.tech-stack {
    text-align: center;
    margin-top: var(--spacing-2xl);
}

.tech-stack-title {
    margin-bottom: var(--spacing-md);
}

.tech-badges {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-sm);
    justify-content: center;
}

.tech-badge {
    background: var(--bg-dark);
    color: white;
    padding: 0.5rem 1rem;
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 0.875rem;
    transition: all var(--transition-base);
}

.tech-badge:hover {
    transform: translateY(-2px);
    background: var(--primary-color);
}

/* ============================================
   Features Section
   ============================================ */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.feature-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border-top: 4px solid var(--primary-color);
}

.section-dark .feature-card {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--primary-light);
}

.section-dark .feature-card h3 {
    color: white;
}

.section-dark .feature-card p,
.section-dark .feature-card ul,
.section-dark .feature-card li {
    color: rgba(255, 255, 255, 0.9);
}

.feature-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.feature-icon {
    width: 70px;
    height: 70px;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    color: white;
    margin-bottom: var(--spacing-md);
}

.feature-icon.ai { background: linear-gradient(135deg, #8b5cf6 0%, #ec4899 100%); }
.feature-icon.power { background: var(--gradient-power); }
.feature-icon.traffic { background: var(--gradient-traffic); }
.feature-icon.v2g { background: var(--gradient-v2g); }
.feature-icon.charging { background: linear-gradient(135deg, #10b981 0%, #059669 100%); }
.feature-icon.viz { background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%); }

.feature-highlight {
    display: inline-block;
    background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%);
    color: #78350f;
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-sm);
}

.feature-list {
    list-style: none;
    margin-top: var(--spacing-md);
}

.feature-list li {
    padding: 0.5rem 0;
    padding-left: 1.5rem;
    position: relative;
    color: var(--text-secondary);
}

.feature-list li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--accent-color);
    font-weight: bold;
}

/* ============================================
   Architecture Section
   ============================================ */
.architecture-diagram {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    margin-bottom: var(--spacing-2xl);
}

.arch-layer {
    margin-bottom: var(--spacing-lg);
}

.arch-header {
    text-align: center;
    font-weight: 700;
    font-size: 1.125rem;
    color: var(--text-primary);
    margin-bottom: var(--spacing-md);
    padding: var(--spacing-sm);
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
}

.arch-components {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
}

.arch-component {
    background: white;
    border: 2px solid var(--border-color);
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    transition: all var(--transition-base);
}

.arch-component:hover {
    border-color: var(--primary-color);
    transform: translateY(-2px);
}

.arch-component.highlight {
    background: var(--gradient-primary);
    color: white;
    border-color: transparent;
}

.arch-component i {
    font-size: 1.25rem;
}

.arch-arrow {
    text-align: center;
    font-size: 2rem;
    color: var(--primary-color);
    margin: var(--spacing-md) 0;
}

.timing-sync {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
}

.timing-sync h3 {
    text-align: center;
    margin-bottom: var(--spacing-lg);
}

.timing-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-lg);
}

.timing-item {
    text-align: center;
    padding: var(--spacing-md);
    background: var(--bg-secondary);
    border-radius: var(--radius-lg);
}

.timing-label {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
    margin-bottom: 0.5rem;
}

.timing-value {
    font-size: 1.75rem;
    font-weight: 800;
    color: var(--primary-color);
    margin-bottom: 0.5rem;
}

.timing-desc {
    font-size: 0.75rem;
    color: var(--text-light);
}

/* ============================================
   Demo Videos Section
   ============================================ */
.main-demo {
    background: white;
    border-radius: var(--radius-2xl);
    box-shadow: var(--shadow-xl);
    overflow: hidden;
    margin-bottom: var(--spacing-2xl);
}

.video-container {
    position: relative;
    padding-bottom: 56.25%; /* 16:9 aspect ratio */
    height: 0;
    overflow: hidden;
}

.video-container iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.video-info {
    padding: var(--spacing-xl);
}

.video-info h3 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.section-dark .video-info h3 {
    color: white;
}

.section-dark .video-info p {
    color: rgba(255, 255, 255, 0.9);
}

.video-meta {
    display: flex;
    gap: var(--spacing-lg);
    margin-top: var(--spacing-md);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.video-meta span {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.feature-demos {
    margin-top: var(--spacing-2xl);
}

.feature-demos-title {
    text-align: center;
    font-size: 2rem;
    margin-bottom: var(--spacing-xl);
}

.feature-demos-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
}

.demo-card {
    background: white;
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    overflow: hidden;
    transition: all var(--transition-base);
}

.demo-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.demo-thumbnail {
    position: relative;
    padding-bottom: 56.25%;
    height: 0;
    overflow: hidden;
    background: var(--bg-dark);
}

.demo-thumbnail iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

.demo-content {
    padding: var(--spacing-lg);
}

.demo-content h4 {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    margin-bottom: var(--spacing-md);
}

.demo-tags {
    display: flex;
    flex-wrap: wrap;
    gap: var(--spacing-xs);
    margin-top: var(--spacing-md);
}

.tag {
    background: var(--bg-secondary);
    color: var(--text-secondary);
    padding: 0.25rem 0.75rem;
    border-radius: var(--radius-md);
    font-size: 0.75rem;
    font-weight: 600;
}

.video-instructions {
    background: #fffbeb;
    border: 2px solid #fbbf24;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.video-instructions h4 {
    color: #d97706;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.video-instructions ol {
    margin-left: var(--spacing-lg);
    color: var(--text-secondary);
}

.video-instructions li {
    margin-bottom: var(--spacing-sm);
}

/* Demo Highlights */
.demo-highlights {
    margin-top: var(--spacing-2xl);
}

.demo-highlights-title {
    text-align: center;
    margin-bottom: var(--spacing-xl);
}

.demo-highlights-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
}

.highlight-card {
    background: white;
    padding: var(--spacing-lg);
    border-radius: var(--radius-lg);
    text-align: center;
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
    border-top: 3px solid var(--primary-color);
}

.section-dark .highlight-card {
    background: rgba(255, 255, 255, 0.05);
    border-color: var(--primary-light);
}

.section-dark .highlight-card h4 {
    color: white;
}

.section-dark .highlight-card p {
    color: rgba(255, 255, 255, 0.9);
}

.section-dark .highlight-card i {
    color: var(--primary-light);
}

.highlight-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.highlight-card i {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
}

.section-dark .demo-highlights-title {
    color: white;
}

.highlight-card h4 {
    margin-bottom: var(--spacing-sm);
    color: var(--text-primary);
}

.highlight-card p {
    font-size: 0.875rem;
    color: var(--text-secondary);
    margin-bottom: 0;
}

/* ============================================
   Publication Section
   ============================================ */
.publication-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(350px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-2xl);
}

.publication-card {
    background: white;
    padding: var(--spacing-xl);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-md);
    transition: all var(--transition-base);
}

.section-dark .publication-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.section-dark .publication-card h3 {
    color: white;
}

.section-dark .publication-card p,
.section-dark .publication-card .paper-title,
.section-dark .publication-card .paper-authors,
.section-dark .publication-card .paper-venue {
    color: rgba(255, 255, 255, 0.9);
}

.section-dark .publication-icon i {
    color: var(--primary-light);
}

.section-dark .btn-primary {
    background: var(--gradient-primary);
    color: white;
}

.section-dark .btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(59, 130, 246, 0.4);
}

.section-dark a {
    color: var(--primary-light);
}

.section-dark a:hover {
    color: white;
}

.publication-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-xl);
}

.publication-icon {
    width: 70px;
    height: 70px;
    background: var(--gradient-primary);
    color: white;
    border-radius: var(--radius-lg);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    margin-bottom: var(--spacing-md);
}

.paper-info {
    margin: var(--spacing-md) 0;
}

.paper-title {
    font-size: 1.125rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-sm);
}

.paper-authors {
    font-style: italic;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-sm);
}

.paper-venue {
    color: var(--text-secondary);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.paper-buttons {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.github-info {
    margin: var(--spacing-md) 0;
}

.github-stats {
    display: flex;
    gap: var(--spacing-lg);
    margin: var(--spacing-md) 0;
}

.github-stat {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.repo-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    background: var(--bg-secondary);
    padding: var(--spacing-md);
    border-radius: var(--radius-md);
    margin: var(--spacing-md) 0;
}

.section-dark .repo-link {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.section-dark .repo-link i {
    color: var(--primary-light);
}

.section-dark .repo-link code {
    background: rgba(255, 255, 255, 0.05);
    color: white;
    border-color: rgba(255, 255, 255, 0.2);
}

.docs-links {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.doc-link {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm);
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.doc-link:hover {
    background: var(--bg-secondary);
    color: var(--primary-color);
    padding-left: var(--spacing-md);
}

.section-dark .doc-link {
    color: rgba(255, 255, 255, 0.9);
}

.section-dark .doc-link:hover {
    background: rgba(255, 255, 255, 0.15);
    color: white;
}

.section-dark .doc-link i {
    color: var(--primary-light);
}

.additional-note {
    background: #eff6ff;
    border: 2px solid #3b82f6;
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.additional-note h4 {
    color: var(--primary-color);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

/* ============================================
   Footer
   ============================================ */
.footer {
    background: var(--bg-dark);
    color: white;
    padding: var(--spacing-3xl) 0 var(--spacing-lg);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: white;
}

.footer-section p {
    color: var(--text-light);
    font-size: 0.875rem;
}

.footer-social {
    display: flex;
    gap: var(--spacing-sm);
    margin-top: var(--spacing-md);
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    transition: all var(--transition-base);
}

.footer-social a:hover {
    background: var(--primary-color);
    transform: translateY(-2px);
}

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

.footer-links li {
    margin-bottom: var(--spacing-sm);
}

.footer-links a {
    color: var(--text-light);
    text-decoration: none;
    font-size: 0.875rem;
    transition: color var(--transition-fast);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.footer-links a:hover {
    color: var(--primary-color);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: var(--spacing-lg);
    text-align: center;
    color: var(--text-light);
    font-size: 0.875rem;
}

.footer-bottom a {
    color: var(--primary-color);
    text-decoration: none;
}

.footer-bottom a:hover {
    text-decoration: underline;
}

/* ============================================
   Back to Top Button
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    width: 50px;
    height: 50px;
    background: var(--gradient-primary);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 1.25rem;
    cursor: pointer;
    box-shadow: var(--shadow-xl);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
}

.back-to-top:hover {
    transform: translateY(-5px);
}

/* ============================================
   Animations
   ============================================ */
@keyframes slideDown {
    from {
        opacity: 0;
        transform: translateY(-20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes bounce {
    0%, 20%, 50%, 80%, 100% {
        transform: translateY(0);
    }
    40% {
        transform: translateY(-10px);
    }
    60% {
        transform: translateY(-5px);
    }
}

/* ============================================
   Responsive Design
   ============================================ */
@media (max-width: 1024px) {
    h1 { font-size: 3rem; }
    h2 { font-size: 2rem; }

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

    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        flex-direction: column;
        background: white;
        width: 100%;
        padding: var(--spacing-lg);
        box-shadow: var(--shadow-lg);
        transition: left var(--transition-base);
    }

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

    .hamburger {
        display: flex;
    }

    .hamburger.active span:nth-child(1) {
        transform: rotate(45deg) translate(5px, 5px);
    }

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

    .hamburger.active span:nth-child(3) {
        transform: rotate(-45deg) translate(7px, -6px);
    }

    h1 { font-size: 2.5rem; }
    h2 { font-size: 1.75rem; }

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

    .hero-stats {
        grid-template-columns: 1fr;
    }

    .hero-buttons {
        flex-direction: column;
    }

    .features-grid {
        grid-template-columns: 1fr;
    }

    .feature-demos-grid {
        grid-template-columns: 1fr;
    }

    .publication-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 var(--spacing-md);
    }

    section {
        padding: var(--spacing-xl) 0;
    }

    h1 { font-size: 2rem; }
    h2 { font-size: 1.5rem; }

    .hero-title {
        font-size: 2rem;
    }

    .stat-value {
        font-size: 1.5rem;
    }
}

/* ============================================
   System Statistics Section
   ============================================ */
.stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--spacing-lg);
    margin-bottom: var(--spacing-2xl);
}

@media (max-width: 1024px) {
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 640px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }
}

.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 16px;
    padding: var(--spacing-xl);
    text-align: center;
    transition: all var(--transition-base);
    position: relative;
    overflow: hidden;
}

.stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient-primary);
    transform: scaleX(0);
    transition: transform var(--transition-base);
}

.stat-card:hover::before {
    transform: scaleX(1);
}

.stat-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 20px 40px rgba(59, 130, 246, 0.15);
}

.section-dark .stat-card {
    background: rgba(255, 255, 255, 0.05);
    border-color: rgba(255, 255, 255, 0.1);
}

.stat-icon {
    font-size: 3rem;
    background: var(--gradient-primary);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: var(--spacing-md);
}

.stat-number {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--primary-color);
    line-height: 1;
    margin-bottom: var(--spacing-sm);
}

.section-dark .stat-number {
    color: white;
}

.stat-label {
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: var(--spacing-xs);
}

.section-dark .stat-label {
    color: rgba(255, 255, 255, 0.9);
}

.stat-detail {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.section-dark .stat-detail {
    color: rgba(255, 255, 255, 0.6);
}

/* Technical Specs */
.technical-specs {
    margin-top: var(--spacing-3xl);
    margin-bottom: var(--spacing-3xl);
}

.specs-title {
    font-size: 2rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: var(--spacing-xl);
    color: var(--text-primary);
}

.section-dark .specs-title {
    color: white;
}

.specs-title i {
    margin-right: var(--spacing-sm);
    color: var(--primary-color);
}

.specs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
}

.spec-category {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: var(--spacing-lg);
}

.spec-category h4 {
    font-size: 1.2rem;
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: white;
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.spec-category h4 i {
    color: var(--primary-light);
}

.spec-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.spec-list li {
    padding: var(--spacing-sm) 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.95rem;
}

.spec-list li:last-child {
    border-bottom: none;
}

.spec-list strong {
    color: white;
    font-weight: 600;
}

/* Infrastructure Details */
.infrastructure-details {
    margin-top: var(--spacing-3xl);
}

/* Video Fallback */
.video-fallback {
    text-align: center;
    margin-top: var(--spacing-md);
    padding: var(--spacing-md);
    background: rgba(59, 130, 246, 0.05);
    border-radius: 8px;
    border: 1px solid rgba(59, 130, 246, 0.2);
}

.video-fallback p {
    margin: 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
}

.video-fallback i.fa-info-circle {
    color: var(--primary-color);
    margin-right: var(--spacing-xs);
}

.youtube-link {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    margin-left: var(--spacing-sm);
    padding: var(--spacing-xs) var(--spacing-md);
    background: #ff0000;
    color: white !important;
    text-decoration: none;
    border-radius: 6px;
    font-weight: 600;
    transition: all var(--transition-base);
}

.youtube-link:hover {
    background: #cc0000;
    transform: translateY(-2px);
    box-shadow: 0 4px 12px rgba(255, 0, 0, 0.3);
}

.youtube-link i {
    font-size: 1.1rem;
}

/* Demo Features List */
.demo-features-list {
    list-style: none;
    padding: 0;
    margin-top: var(--spacing-md);
}

.demo-features-list li {
    padding: var(--spacing-sm) 0;
    color: var(--text-secondary);
    font-size: 0.95rem;
    line-height: 1.6;
    display: flex;
    align-items: flex-start;
    gap: var(--spacing-sm);
}

.demo-features-list li i {
    color: var(--accent-color);
    margin-top: 4px;
    flex-shrink: 0;
}

.demo-features-list li strong {
    color: var(--primary-color);
    font-weight: 600;
}

.substation-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.substation-card {
    background: rgba(255, 255, 255, 0.05);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 12px;
    padding: var(--spacing-lg);
    transition: all var(--transition-base);
}

.substation-card:hover {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--primary-color);
    transform: translateY(-3px);
}

.substation-card h4 {
    font-size: 1.3rem;
    font-weight: 700;
    color: white;
    margin-bottom: var(--spacing-md);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: var(--spacing-sm);
}

.substation-card p {
    margin: var(--spacing-sm) 0;
    color: rgba(255, 255, 255, 0.8);
    font-size: 0.95rem;
}

.substation-card i {
    color: var(--primary-light);
    margin-right: var(--spacing-xs);
    width: 20px;
}

/* ============================================
   Print Styles
   ============================================ */
@media print {
    .navbar,
    .hero-buttons,
    .back-to-top,
    .footer {
        display: none;
    }

    body {
        color: black;
    }

    .section {
        page-break-inside: avoid;
    }
}