:root {
    --font-sans: 'Source Sans 3', system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
    
    --color-background: #000000;
    --color-surface: #0d0d0d;
    --color-elevated: #100d14;
    --color-elevated-hover: #1a1620;
    --color-foreground: #ffffff;
    --color-foreground-muted: #b8b4bc;
    --color-foreground-subtle: #96929b;
    
    --color-accent: #00CED1;
    --color-accent-light: #48D1CC;
    --color-accent-dark: #20B2AA;
    --color-accent-glow: rgba(0, 206, 209, 0.2);
    
    --color-border: rgba(255, 255, 255, 0.08);
    --color-border-strong: rgba(255, 255, 255, 0.15);
    
    --color-success: #4ade80;
    --color-warning: #fbbf24;
    --color-error: #f87171;
    
    --margin-xs: 0.25rem;
    --margin-sm: 0.5rem;
    --margin-md: 1rem;
    --margin-lg: 1.5rem;
    --margin-xl: 2rem;
    --margin-2xl: 3rem;
    
    --radius-sm: 0.375rem;
    --radius-md: 0.5rem;
    --radius-lg: 0.75rem;
    --radius-xl: 1rem;
    
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.2);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.5), 0 4px 6px -2px rgba(0, 0, 0, 0.3);
    --shadow-glow: 0 0 20px var(--color-accent-glow);
    
    --transition-fast: 100ms ease;
    --transition-base: 150ms ease;
    --transition-slow: 200ms ease;
    
    --navbar-height: 4rem;
    --container-max: 72rem;
}

@media (prefers-color-scheme: light) {
    :root:not([data-theme="dark"]) {
        --color-background: #fafafa;
        --color-surface: #ffffff;
        --color-elevated: #f5f5f5;
        --color-elevated-hover: #eeeeee;
        --color-foreground: #1a1a1a;
        --color-foreground-muted: #4a4a4a;
        --color-foreground-subtle: #6b7280;
        
        --color-accent: #008B8B;
        --color-accent-light: #20B2AA;
        --color-accent-dark: #006666;
        --color-accent-glow: rgba(0, 139, 139, 0.15);
        
        --color-border: rgba(0, 0, 0, 0.08);
        --color-border-strong: rgba(0, 0, 0, 0.15);
        
        --shadow-sm: 0 1px 2px 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, 0.05);
        --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    }
}

[data-theme="light"] {
    --color-background: #fafafa;
    --color-surface: #ffffff;
    --color-elevated: #f5f5f5;
    --color-elevated-hover: #eeeeee;
    --color-foreground: #1a1a1a;
    --color-foreground-muted: #4a4a4a;
    --color-foreground-subtle: #6b7280;
    
    --color-accent: #008B8B;
    --color-accent-light: #20B2AA;
    --color-accent-dark: #006666;
    --color-accent-glow: rgba(0, 139, 139, 0.15);
    
    --color-border: rgba(0, 0, 0, 0.08);
    --color-border-strong: rgba(0, 0, 0, 0.15);
    
    --shadow-sm: 0 1px 2px 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, 0.05);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

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

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
    
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

body {
    font-family: var(--font-sans);
    background-color: var(--color-background);
    color: var(--color-foreground);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.3;
    color: var(--color-foreground);
}

h1 { font-size: clamp(2rem, 5vw, 2.75rem); letter-spacing: -0.02em; }
h2 { font-size: clamp(1.25rem, 3vw, 1.5rem); }
h3 { font-size: 1.125rem; }

p {
    color: var(--color-foreground-muted);
    line-height: 1.7;
}

a {
    color: var(--color-accent);
    text-decoration: none;
    transition: color var(--transition-fast);
}

a:hover {
    color: var(--color-accent-light);
}

a:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

ul {
    list-style: none;
}

.skip-link {
    position: absolute;
    top: -100%;
    left: 50%;
    transform: translateX(-50%);
    background: var(--color-accent);
    color: white;
    padding: var(--margin-sm) var(--margin-lg);
    border-radius: var(--radius-md);
    font-weight: 600;
    z-index: 10000;
    transition: top var(--transition-fast);
}

.skip-link:focus {
    top: var(--margin-md);
}

.container {
    width: 100%;
    max-width: var(--container-max);
    margin: 0 auto;
    padding: 0 var(--margin-xl);
}

.navbar {
    position: sticky;
    top: 0;
    background-color: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    backdrop-filter: blur(12px);
    z-index: 1000;
    transition: background-color var(--transition-base), 
                box-shadow var(--transition-base);
}



.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: var(--navbar-height);
}

.navbar-brand {
    display: flex;
    align-items: center;
    gap: var(--margin-sm);
    color: var(--color-foreground);
    font-size: 1.25rem;
    font-weight: 700;
    text-decoration: none;
    transition: opacity var(--transition-fast);
}

.navbar-brand:hover {
    opacity: 0.8;
    color: var(--color-foreground);
}

.brand-icon {
    font-size: 1.5rem;
}

.nav-links {
    display: none;
    gap: var(--margin-lg);
}

@media (min-width: 768px) {
    .nav-links {
        display: flex;
    }
}

.nav-link {
    color: var(--color-foreground-muted);
    font-weight: 500;
    font-size: 0.9375rem;
    padding: var(--margin-xs) 0;
    position: relative;
}

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

.nav-link:hover,
.nav-link:focus {
    color: var(--color-foreground);
}

.nav-link:hover::after,
.nav-link:focus::after {
    width: 100%;
}

.theme-toggle {
    background: transparent;
    border: none;
    border-radius: var(--radius-md);
    padding: var(--margin-sm);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
    background-color: var(--color-elevated);
    border-color: var(--color-accent);
}

.theme-toggle:focus-visible {
    outline: 2px solid var(--color-accent);
    outline-offset: 2px;
}

.theme-icon {
    font-size: 1.25rem;
    line-height: 1;
    color: var(--color-foreground);
}

.theme-icon svg {
    width: 1.25rem;
    height: 1.25rem;
    display: block;
}

.theme-icon.dark {
    display: none;
}

[data-theme="dark"] .theme-icon.light {
    display: none;
}

[data-theme="dark"] .theme-icon.dark {
    display: block;
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .theme-icon.light {
        display: none;
    }
    
    :root:not([data-theme="light"]) .theme-icon.dark {
        display: block;
    }
}

.hero {
    padding: var(--margin-2xl) 0;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: calc(60vh - var(--navbar-height));
}

.hero-content {
    max-width: 48rem;
    animation: fadeInUp 0.4s ease-out;
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.hero-badge {
    display: inline-block;
    background: var(--color-accent-glow);
    color: var(--color-accent);
    padding: var(--margin-xs) var(--margin-md);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    font-weight: 600;
    margin-bottom: var(--margin-lg);
    border: 1px solid var(--color-accent-glow);
}

.hero h1 {
    margin-bottom: var(--margin-md);
    background: linear-gradient(135deg, var(--color-foreground) 0%, var(--color-foreground-muted) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1.125rem, 2.5vw, 1.5rem);
    color: var(--color-foreground);
    font-weight: 600;
    margin-bottom: var(--margin-md);
}

.hero-description {
    font-size: 1.125rem;
    max-width: 36rem;
    margin: 0 auto var(--margin-xl);
    color: var(--color-foreground-muted);
}

.hero-actions {
    display: flex;
    gap: var(--margin-md);
    justify-content: center;
    flex-wrap: wrap;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--margin-sm);
    padding: var(--margin-md) var(--margin-xl);
    border-radius: var(--radius-md);
    font-weight: 600;
    font-size: 1rem;
    transition: all var(--transition-fast);
    text-decoration: none;
}

.btn-primary {
    background: var(--color-accent);
    color: white;
    border: 1px solid var(--color-accent);
}

.btn-primary:hover {
    background: var(--color-accent-light);
    border-color: var(--color-accent-light);
    color: white;
    transform: translateY(-2px);
    box-shadow: var(--shadow-glow);
}

.btn-secondary {
    background: transparent;
    color: var(--color-foreground);
    border: 1px solid var(--color-border-strong);
}

.btn-secondary:hover {
    background: var(--color-elevated);
    border-color: var(--color-accent);
    color: var(--color-foreground);
}

.btn .icon {
    width: 1.25rem;
    height: 1.25rem;
}

.grid {
    display: grid;
    grid-template-columns: 1fr;
    gap: var(--margin-xl);
    padding-bottom: var(--margin-2xl);
}

@media (min-width: 768px) {
    .grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid-full {
        grid-column: span 2;
    }
}

@media (min-width: 1024px) {
    .grid {
        grid-template-columns: repeat(6, 1fr);
    }
    
    .grid-full {
        grid-column: span 6;
    }
    
    .grid-2 {
        grid-column: span 3;
    }
    
    .grid-3 {
        grid-column: span 2;
    }
}

.card {
    background-color: var(--color-elevated);
    border-radius: var(--radius-lg);
    padding: var(--margin-xl);
    height: 100%;
    border: 1px solid var(--color-border);
    transition: transform var(--transition-base), 
                box-shadow var(--transition-base),
                border-color var(--transition-fast);
    position: relative;
    overflow: hidden;
    content-visibility: auto;
    contain-intrinsic-size: 0 300px;
    will-change: transform;
}

.card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--color-accent) 0%, var(--color-accent-light) 100%);
    opacity: 0;
    transition: opacity var(--transition-fast);
}

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

.card:hover::before {
    opacity: 1;
}

/* Card entrance animations - optimized for performance */
.card-animate {
    opacity: 0;
    transform: translateY(8px);
    transition: opacity 0.2s ease-out, transform 0.2s ease-out;
}

.card-animate.card-visible {
    opacity: 1;
    transform: translateY(0);
}

.card h2 {
    margin-bottom: var(--margin-md);
    color: var(--color-foreground);
}

.card h3 {
    margin-top: var(--margin-lg);
    margin-bottom: var(--margin-sm);
    color: var(--color-foreground);
}

.card h3:first-of-type {
    margin-top: 0;
}

.psection {
    margin-top: var(--margin-md);
}

.stats-card {
    padding: var(--margin-lg);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: var(--margin-lg);
}

@media (min-width: 768px) {
    .stats-grid {
        grid-template-columns: repeat(4, 1fr);
    }
}

.stat-item {
    text-align: center;
    padding: var(--margin-md);
}

.stat-value {
    display: block;
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-accent);
    font-family: var(--font-mono);
}

.stat-label {
    display: block;
    font-size: 0.875rem;
    color: var(--color-foreground-subtle);
    margin-top: var(--margin-xs);
}

.code-block {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--margin-md);
    margin: var(--margin-md) 0;
    overflow-x: auto;
}

.code-block pre {
    margin: 0;
    font-family: var(--font-mono);
    font-size: 0.875rem;
    line-height: 1.6;
}

.code-block code {
    color: var(--color-foreground);
}

.code-block .comment {
    color: var(--color-foreground-subtle);
}

.note {
    font-size: 0.9375rem;
    color: var(--color-foreground-muted);
    margin-top: var(--margin-md);
}

.team-list li,
.doc-list li {
    padding: var(--margin-xs) 0;
    color: var(--color-foreground-muted);
}

.doc-list a {
    display: flex;
    align-items: center;
    gap: var(--margin-sm);
    padding: var(--margin-xs) 0;
    transition: transform var(--transition-fast);
}

.doc-list a:hover {
    transform: translateX(4px);
}

.doc-icon {
    display: flex;
    align-items: center;
    justify-content: center;
}

.doc-icon svg {
    width: 1.25rem;
    height: 1.25rem;
    color: var(--color-accent);
    flex-shrink: 0;
}

.repo-list {
    display: flex;
    flex-direction: column;
    gap: var(--margin-md);
}

.repo-link {
    display: block;
    padding: var(--margin-md);
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: all var(--transition-fast);
}

.repo-link:hover {
    border-color: var(--color-accent);
    background: var(--color-elevated-hover);
    transform: translateY(-2px);
}

.repo-name {
    display: block;
    font-weight: 600;
    color: var(--color-foreground);
    margin-bottom: var(--margin-xs);
}

.repo-desc {
    display: block;
    font-size: 0.875rem;
    color: var(--color-foreground-subtle);
}

.details-grid {
    display: grid;
    gap: var(--margin-xl);
}

@media (min-width: 768px) {
    .details-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

.detail-item h3 {
    color: var(--color-accent);
    margin-bottom: var(--margin-sm);
}

.tech-grid {
    display: grid;
    gap: var(--margin-lg);
}

@media (min-width: 640px) {
    .tech-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (min-width: 1024px) {
    .tech-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

.tech-category h3 {
    color: var(--color-foreground);
    margin-bottom: var(--margin-sm);
    font-size: 1rem;
}

.tech-list {
    display: flex;
    flex-wrap: wrap;
    gap: var(--margin-sm);
}

.tech-tag {
    display: inline-block;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    padding: var(--margin-xs) var(--margin-sm);
    border-radius: var(--radius-sm);
    font-size: 0.875rem;
    color: var(--color-foreground-muted);
    font-family: var(--font-mono);
    transition: all var(--transition-fast);
}

.tech-tag:hover {
    border-color: var(--color-accent);
    color: var(--color-accent);
}

.faq-card h2 {
    margin-bottom: var(--margin-lg);
}

.faq-list {
    display: flex;
    flex-direction: column;
    gap: var(--margin-md);
}

.faq-item {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.faq-item summary {
    padding: var(--margin-md) var(--margin-lg);
    cursor: pointer;
    font-weight: 600;
    color: var(--color-foreground);
    list-style: none;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color var(--transition-fast);
}

.faq-item summary:hover {
    background-color: var(--color-elevated-hover);
}

.faq-item summary::-webkit-details-marker {
    display: none;
}

.faq-item summary::after {
    content: '+';
    font-size: 1.25rem;
    color: var(--color-accent);
    transition: transform var(--transition-fast);
}

.faq-item[open] summary::after {
    transform: rotate(45deg);
}

.faq-item p {
    padding: 0 var(--margin-lg) var(--margin-md);
    font-size: 0.9375rem;
    animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
    from { opacity: 0; }
    to { opacity: 1; }
}

.back-to-top {
    position: fixed;
    bottom: var(--margin-xl);
    right: var(--margin-xl);
    width: 3rem;
    height: 3rem;
    background: var(--color-elevated);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-fast);
    z-index: 999;
    box-shadow: var(--shadow-md);
}

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

.back-to-top:hover {
    background: var(--color-accent);
    border-color: var(--color-accent);
    transform: translateY(-2px);
}

.back-to-top svg {
    width: 1.5rem;
    height: 1.5rem;
    color: var(--color-foreground);
}

footer {
    margin-top: auto;
    background: var(--color-surface);
    border-top: 1px solid var(--color-border);
}

.footer-content {
    display: flex;
    flex-direction: column;
    gap: var(--margin-lg);
    padding: var(--margin-2xl) var(--margin-xl);
    text-align: center;
}

@media (min-width: 640px) {
    .footer-content {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
        text-align: left;
    }
}

.footer-brand {
    display: flex;
    align-items: center;
    gap: var(--margin-sm);
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--color-foreground);
}

.footer-affiliation {
    margin-top: var(--margin-sm);
    font-size: 0.875rem;
    color: var(--color-foreground-subtle);
    line-height: 1.5;
}

.footer-links {
    display: flex;
    gap: var(--margin-md);
    justify-content: center;
}

.footer-links a {
    color: var(--color-foreground-muted);
    transition: color var(--transition-fast);
}

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

.footer-links .icon {
    width: 1.5rem;
    height: 1.5rem;
}

.footer-bottom {
    background: var(--color-background);
    border-top: 1px solid var(--color-border);
    padding: var(--margin-md) 0;
}

.footer-bottom p {
    text-align: center;
    font-size: 0.875rem;
    color: var(--color-foreground-subtle);
}

@media print {
    .navbar,
    .back-to-top,
    .theme-toggle,
    .hero-actions,
    .footer-links {
        display: none !important;
    }
    
    body {
        background: white;
        color: black;
    }
    
    .card {
        background: white;
        border: 1px solid #ccc;
        break-inside: avoid;
    }
    
    a {
        color: #000;
        text-decoration: underline;
    }
    
    a[href]::after {
        content: " (" attr(href) ")";
        font-size: 0.8em;
        color: #666;
    }
}

@media (max-width: 767px) {
    .container {
        padding: 0 var(--margin-md);
    }
    
    .hero {
        min-height: auto;
        padding: var(--margin-xl) 0;
    }
    
    .hero-actions {
        flex-direction: column;
        align-items: center;
        padding: 0 var(--margin-md);
    }
    
    .btn {
        justify-content: center;
        width: 100%;
        max-width: 300px;
    }
    
    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid-2 {
        grid-column: span 1;
    }
}