/* ============================================
   GRADIENT ASCENT - Premium Design System
   "From Zero to Autonomous"
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    /* Colors - Premium Dark Theme */
    --bg-primary: #050508;
    --bg-secondary: #0a0a10;
    --bg-tertiary: #10101a;
    --bg-card: rgba(20, 20, 35, 0.6);
    --bg-card-hover: rgba(30, 30, 50, 0.8);
    --bg-glass: rgba(15, 15, 25, 0.7);

    --text-primary: #f5f5fa;
    --text-secondary: #a8a8c0;
    --text-muted: #5a5a70;

    --accent-cyan: #00e5ff;
    --accent-purple: #b366ff;
    --accent-pink: #ff66b2;
    --accent-blue: #4d79ff;
    --accent-gradient: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-purple) 50%, var(--accent-pink) 100%);
    --accent-gradient-subtle: linear-gradient(135deg, rgba(0, 229, 255, 0.1), rgba(179, 102, 255, 0.1));

    --glow-cyan: 0 0 30px rgba(0, 229, 255, 0.4);
    --glow-purple: 0 0 30px rgba(179, 102, 255, 0.4);
    --glow-soft: 0 0 60px rgba(0, 229, 255, 0.15);

    --border-color: rgba(255, 255, 255, 0.08);
    --border-glow: rgba(0, 229, 255, 0.3);

    /* Typography */
    --font-main: 'Space Grotesk', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-mono: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;

    /* Spacing */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 5rem;

    /* Transitions */
    --transition-fast: 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-normal: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 0.5s cubic-bezier(0.4, 0, 0.2, 1);
    --transition-bounce: 0.5s cubic-bezier(0.34, 1.56, 0.64, 1);

    /* Border Radius */
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --radius-full: 9999px;

    /* Shadows */
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 32px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 64px rgba(0, 0, 0, 0.5);
    --shadow-glow: 0 0 40px rgba(0, 229, 255, 0.2);
}

/* ---------- Reset & Base ---------- */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

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

body {
    font-family: var(--font-main);
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.7;
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

/* Animated Background */
body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse 80% 50% at 20% 40%, rgba(0, 229, 255, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse 60% 40% at 80% 60%, rgba(179, 102, 255, 0.08) 0%, transparent 50%),
        radial-gradient(ellipse 40% 30% at 40% 80%, rgba(255, 102, 178, 0.05) 0%, transparent 50%);
    pointer-events: none;
    z-index: -1;
    animation: bgShift 20s ease-in-out infinite alternate;
}

@keyframes bgShift {
    0% {
        opacity: 1;
        transform: scale(1);
    }

    100% {
        opacity: 0.7;
        transform: scale(1.1);
    }
}

/* Noise texture overlay */
body::after {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 256 256' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='noise'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='3' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23noise)'/%3E%3C/svg%3E");
    opacity: 0.03;
    pointer-events: none;
    z-index: -1;
}

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

ul,
ol {
    list-style: none;
}

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

/* ---------- Typography ---------- */
h1,
h2,
h3,
h4,
h5,
h6 {
    font-weight: 600;
    line-height: 1.2;
    letter-spacing: -0.02em;
}

h1 {
    font-size: clamp(2.5rem, 5vw, 4rem);
}

h2 {
    font-size: clamp(1.75rem, 3vw, 2.5rem);
}

h3 {
    font-size: clamp(1.25rem, 2vw, 1.75rem);
}

h4 {
    font-size: 1.25rem;
}

.gradient-text {
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

/* ---------- Layout ---------- */
.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 var(--spacing-md);
}

/* ---------- Glassmorphism Card ---------- */
.glass-card {
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
}

/* ---------- Navigation ---------- */
.navbar {
    position: relative;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: var(--spacing-md) var(--spacing-lg);
    background: transparent;
    border-bottom: none;
    transition: all var(--transition-normal);
}

.navbar.scrolled {
    background: rgba(5, 5, 8, 0.95);
    box-shadow: var(--shadow-md);
}

.navbar-content {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 700;
    font-size: 1.25rem;
    transition: transform var(--transition-bounce);
}

.logo:hover {
    transform: scale(1.05);
}

.logo-symbol {
    font-size: 1.75rem;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: pulse 3s ease-in-out infinite;
}

@keyframes pulse {

    0%,
    100% {
        opacity: 1;
        filter: brightness(1);
    }

    50% {
        opacity: 0.8;
        filter: brightness(1.3);
    }
}

.nav-links {
    display: flex;
    gap: var(--spacing-lg);
    align-items: center;
}

.nav-links a {
    color: var(--text-secondary);
    font-weight: 500;
    position: relative;
    padding: var(--spacing-xs) 0;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    transition: width var(--transition-normal);
}

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

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

/* Mobile Nav Toggle */
.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: var(--spacing-xs);
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: var(--radius-full);
    transition: all var(--transition-normal);
}

/* ---------- Buttons ---------- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1rem;
    cursor: pointer;
    transition: all var(--transition-normal);
    border: none;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255, 255, 255, 0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--accent-gradient);
    color: var(--bg-primary);
    box-shadow: var(--glow-soft);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
}

.btn-primary:active {
    transform: translateY(-1px);
}

.btn-secondary {
    background: transparent;
    color: var(--text-primary);
    border: 1px solid var(--border-color);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    border-color: var(--accent-cyan);
    background: rgba(0, 229, 255, 0.1);
    box-shadow: var(--glow-cyan);
}

/* ---------- Hero Section ---------- */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: var(--spacing-lg) var(--spacing-md);
    position: relative;
}

.hero-content {
    position: relative;
    z-index: 1;
    max-width: 900px;
}

.hero-logo {
    font-size: clamp(4rem, 10vw, 7rem);
    margin-bottom: var(--spacing-sm);
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    animation: float 4s ease-in-out infinite;
    filter: drop-shadow(0 0 30px rgba(0, 229, 255, 0.5));
}

@keyframes float {

    0%,
    100% {
        transform: translateY(0) rotate(0deg);
    }

    25% {
        transform: translateY(-15px) rotate(-2deg);
    }

    75% {
        transform: translateY(-5px) rotate(2deg);
    }
}

.hero h1 {
    margin-bottom: var(--spacing-sm);
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.hero-tagline {
    font-size: clamp(1.25rem, 2.5vw, 1.75rem);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    font-style: italic;
    animation: fadeInUp 0.8s ease-out 0.4s both;
}

.hero-description {
    font-size: 1.125rem;
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    max-width: 650px;
    margin-left: auto;
    margin-right: auto;
    animation: fadeInUp 0.8s ease-out 0.6s both;
}

.hero-cta {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease-out 0.8s both;
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ---------- Path Preview ---------- */
.path-preview {
    margin-top: var(--spacing-2xl);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-xs);
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease-out 1s both;
}

.path-node {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-md) var(--spacing-lg);
    background: var(--bg-glass);
    backdrop-filter: blur(10px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
}

.path-node::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--accent-gradient);
    transform: scaleX(0);
    transition: transform var(--transition-normal);
}

.path-node:hover {
    border-color: var(--accent-cyan);
    transform: translateY(-8px) scale(1.05);
    box-shadow: var(--glow-cyan), var(--shadow-lg);
}

.path-node:hover::before {
    transform: scaleX(1);
}

.path-node-emoji {
    font-size: 2rem;
    transition: transform var(--transition-bounce);
}

.path-node:hover .path-node-emoji {
    transform: scale(1.2);
}

.path-node-label {
    font-size: 0.875rem;
    font-weight: 600;
    color: var(--text-secondary);
}

.path-arrow {
    color: var(--text-muted);
    font-size: 1.5rem;
    animation: arrowPulse 2s ease-in-out infinite;
}

@keyframes arrowPulse {

    0%,
    100% {
        opacity: 0.5;
        transform: translateX(0);
    }

    50% {
        opacity: 1;
        transform: translateX(5px);
    }
}

/* ---------- Roadmap Page ---------- */
.roadmap-page {
    padding-top: var(--spacing-lg);
    min-height: 100vh;
    padding-bottom: var(--spacing-2xl);
}

.roadmap-header {
    text-align: center;
    padding: var(--spacing-xl) var(--spacing-md);
    margin-bottom: var(--spacing-xl);
}

.roadmap-header h1 {
    margin-bottom: var(--spacing-sm);
}

.roadmap-header p {
    color: var(--text-secondary);
    font-size: 1.125rem;
}

/* ---------- Tree Container ---------- */
.tree-container {
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--spacing-md);
    max-width: 1000px;
    margin: 0 auto;
}

.tree-tier {
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
    width: 100%;
}

.tier-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 3px;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    font-weight: 500;
}

.tier-node {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-lg) var(--spacing-xl);
    background: var(--bg-glass);
    backdrop-filter: blur(20px);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    cursor: pointer;
    transition: all var(--transition-normal);
    position: relative;
    overflow: hidden;
    min-width: 320px;
}

.tier-node::before {
    content: '';
    position: absolute;
    inset: 0;
    background: var(--accent-gradient);
    opacity: 0;
    transition: opacity var(--transition-normal);
}

.tier-node::after {
    content: '';
    position: absolute;
    inset: 1px;
    background: var(--bg-tertiary);
    border-radius: calc(var(--radius-xl) - 1px);
    z-index: 0;
}

.tier-node>* {
    position: relative;
    z-index: 1;
}

.tier-node:hover {
    transform: scale(1.03);
    box-shadow: var(--shadow-glow);
}

.tier-node:hover::before {
    opacity: 1;
}

.tier-node-emoji {
    font-size: 2.5rem;
    transition: transform var(--transition-bounce);
}

.tier-node:hover .tier-node-emoji {
    transform: scale(1.15) rotate(-5deg);
}

.tier-node-content h3 {
    font-size: 1.35rem;
    margin-bottom: 0.25rem;
}

.tier-node-content p {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.tree-line {
    width: 3px;
    height: 50px;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
    position: relative;
}

.tree-line::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 12px;
    height: 12px;
    background: var(--accent-cyan);
    border-radius: 50%;
    box-shadow: var(--glow-cyan);
    animation: linePulse 2s ease-in-out infinite;
}

@keyframes linePulse {

    0%,
    100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }

    50% {
        opacity: 0.5;
        transform: translate(-50%, -50%) scale(0.8);
    }
}

/* Subtopics grid */
.subtopics-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-sm);
    width: 100%;
    max-width: 800px;
}

.subtopic-node {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    padding: var(--spacing-sm) var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-normal);
    font-size: 0.9rem;
    font-weight: 500;
}

.subtopic-node:hover {
    border-color: var(--accent-cyan);
    background: var(--bg-card-hover);
    transform: translateX(5px);
    box-shadow: var(--shadow-sm);
}

.subtopic-node .emoji {
    font-size: 1.25rem;
    transition: transform var(--transition-bounce);
}

.subtopic-node:hover .emoji {
    transform: scale(1.2);
}

/* ---------- Topic Page ---------- */
.topic-page {
    padding-top: 0;
    min-height: 100vh;
    display: flex;
}

.topic-sidebar {
    width: var(--sidebar-width, 300px);
    min-width: 200px;
    max-width: 500px;
    position: sticky;
    left: 0;
    top: 0;
    height: 100vh;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    overflow-y: auto;
    padding: var(--spacing-lg);
    z-index: 100;
    flex-shrink: 0;
}

/* Sidebar Resizer */
.sidebar-resizer {
    width: 6px;
    background: transparent;
    cursor: col-resize;
    position: relative;
    flex-shrink: 0;
    transition: background var(--transition-fast);
    z-index: 101;
}

.sidebar-resizer::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 4px;
    height: 40px;
    background: var(--border-color);
    border-radius: var(--radius-full);
    opacity: 0;
    transition: opacity var(--transition-normal), background var(--transition-normal);
}

.sidebar-resizer:hover {
    background: rgba(0, 229, 255, 0.1);
}

.sidebar-resizer:hover::before {
    opacity: 1;
    background: var(--accent-cyan);
}

.sidebar-resizer.dragging {
    background: rgba(0, 229, 255, 0.2);
}

.sidebar-resizer.dragging::before {
    opacity: 1;
    background: var(--accent-cyan);
    box-shadow: var(--glow-cyan);
}

body.resizing {
    cursor: col-resize !important;
    user-select: none;
}

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

.sidebar-title {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 2px;
    color: var(--text-muted);
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    font-weight: 600;
}

.sidebar-category {
    margin-bottom: var(--spacing-sm);
}

.category-header {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    cursor: pointer;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    font-weight: 500;
}

.category-header:hover {
    background: var(--bg-card);
}

.category-header .arrow {
    transition: transform var(--transition-fast);
    color: var(--text-muted);
    font-size: 0.7rem;
}

.category-header.open .arrow {
    transform: rotate(90deg);
}

.category-items {
    display: none;
    padding-left: var(--spacing-lg);
    margin-top: var(--spacing-xs);
}

.category-items.open {
    display: block;
}

.sidebar-link {
    display: block;
    padding: var(--spacing-xs) var(--spacing-sm);
    color: var(--text-secondary);
    font-size: 0.875rem;
    border-radius: var(--radius-sm);
    transition: all var(--transition-fast);
    margin-bottom: 2px;
    position: relative;
}

.sidebar-link::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    transform: translateY(-50%);
    width: 2px;
    height: 0;
    background: var(--accent-cyan);
    border-radius: var(--radius-full);
    transition: height var(--transition-fast);
}

.sidebar-link:hover {
    color: var(--text-primary);
    background: var(--bg-card);
    padding-left: var(--spacing-md);
}

.sidebar-link:hover::before {
    height: 60%;
}

.sidebar-link.active {
    color: var(--accent-cyan);
    background: rgba(0, 229, 255, 0.1);
    padding-left: var(--spacing-md);
}

.sidebar-link.active::before {
    height: 60%;
}

/* Topic Content */
.topic-content {
    flex: 1;
    padding: var(--spacing-xl) var(--spacing-2xl);
    max-width: 900px;
}

.topic-header {
    margin-bottom: var(--spacing-xl);
    padding-bottom: var(--spacing-lg);
    border-bottom: 1px solid var(--border-color);
}

.topic-breadcrumb {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: var(--spacing-sm);
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.topic-breadcrumb a {
    color: var(--text-secondary);
}

.topic-breadcrumb a:hover {
    color: var(--accent-cyan);
}

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

.topic-title h1 {
    font-size: clamp(2rem, 4vw, 2.75rem);
}

.topic-title .emoji {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
}

.topic-tagline {
    font-size: 1.25rem;
    color: var(--text-secondary);
    font-style: italic;
}

/* Topic Sections */
.topic-section {
    margin-bottom: var(--spacing-xl);
}

.topic-section h2 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
}

.topic-section h2::before {
    content: '';
    width: 4px;
    height: 1.5rem;
    background: var(--accent-gradient);
    border-radius: var(--radius-full);
}

.topic-section p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
    line-height: 1.8;
}

.topic-section ul {
    margin-left: var(--spacing-md);
}

.topic-section li {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xs);
    position: relative;
    padding-left: var(--spacing-md);
}

.topic-section li::before {
    content: '→';
    position: absolute;
    left: 0;
    color: var(--accent-cyan);
}

/* Resources */
.resources-grid {
    display: grid;
    gap: var(--spacing-sm);
}

.resource-card {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    padding: var(--spacing-md);
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    transition: all var(--transition-normal);
}

.resource-card:hover {
    border-color: var(--accent-cyan);
    background: var(--bg-card-hover);
    transform: translateX(8px);
    box-shadow: var(--shadow-sm);
}

.resource-icon {
    font-size: 1.75rem;
    width: 56px;
    height: 56px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--bg-secondary);
    border-radius: var(--radius-md);
}

.resource-info h4 {
    margin-bottom: 0.25rem;
    font-size: 1rem;
}

.resource-info p {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin: 0;
}

/* Code blocks */
.code-block {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: var(--spacing-md);
    overflow-x: auto;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    line-height: 1.7;
    margin-bottom: var(--spacing-md);
    position: relative;
}

.code-block::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: var(--accent-purple);
    border-radius: var(--radius-full) 0 0 var(--radius-full);
}

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

/* Math blocks */
.math-block {
    background: var(--bg-secondary);
    border-left: 3px solid var(--accent-cyan);
    padding: var(--spacing-md) var(--spacing-lg);
    margin: var(--spacing-md) 0;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    overflow-x: auto;
}

.topic-section .katex {
    font-size: 1.1em;
}

.topic-section .katex-display {
    margin: var(--spacing-sm) 0;
}

/* Tables */
.topic-section table {
    width: 100%;
    border-collapse: collapse;
    margin: var(--spacing-md) 0;
    background: var(--bg-card);
    border-radius: var(--radius-md);
    overflow: hidden;
}

.topic-section th,
.topic-section td {
    padding: var(--spacing-sm) var(--spacing-md);
    text-align: left;
    border-bottom: 1px solid var(--border-color);
}

.topic-section th {
    background: var(--bg-secondary);
    font-weight: 600;
    color: var(--text-primary);
}

.topic-section td {
    color: var(--text-secondary);
}

.topic-section tr:last-child td {
    border-bottom: none;
}

/* Topic notes headings */
.topic-section h3 {
    font-size: 1.2rem;
    color: var(--accent-cyan);
    margin: var(--spacing-lg) 0 var(--spacing-sm);
}

.topic-section h3:first-child {
    margin-top: 0;
}

/* Ordered lists */
.topic-section ol {
    margin-left: var(--spacing-md);
    counter-reset: item;
}

.topic-section ol li {
    counter-increment: item;
    padding-left: var(--spacing-md);
}

.topic-section ol li::before {
    content: counter(item) ".";
    color: var(--accent-purple);
    font-weight: 600;
}

/* ---------- Footer ---------- */
.footer {
    padding: var(--spacing-xl) var(--spacing-md);
    border-top: 1px solid var(--border-color);
    text-align: center;
    background: var(--bg-secondary);
}

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

.footer a {
    color: var(--accent-cyan);
    font-weight: 500;
}

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

/* ---------- Mobile Menu Overlay ---------- */
.mobile-menu {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(5, 5, 8, 0.95);
    backdrop-filter: blur(20px);
    z-index: 999;
    padding: 100px var(--spacing-lg);
    flex-direction: column;
    gap: var(--spacing-lg);
}

.mobile-menu.active {
    display: flex;
}

.mobile-menu a {
    font-size: 1.5rem;
    font-weight: 600;
    color: var(--text-primary);
    padding: var(--spacing-sm);
    border-bottom: 1px solid var(--border-color);
}

/* ---------- Responsive ---------- */
@media (max-width: 1024px) {
    .topic-sidebar {
        width: 260px;
    }

    .topic-content {
        margin-left: 260px;
        padding: var(--spacing-lg);
    }
}

@media (max-width: 768px) {

    /* Navigation */
    .nav-links {
        display: none;
    }

    .nav-toggle {
        display: flex;
    }

    /* Hero */
    .hero {
        padding: calc(var(--spacing-2xl) + 40px) var(--spacing-md) var(--spacing-xl);
    }

    .hero-cta {
        flex-direction: column;
        align-items: center;
    }

    .btn {
        width: 100%;
        max-width: 280px;
    }

    /* Path Preview */
    .path-preview {
        flex-direction: column;
        gap: var(--spacing-sm);
    }

    .path-arrow {
        transform: rotate(90deg);
    }

    .path-node {
        width: 100%;
        max-width: 280px;
    }

    /* Tree */
    .tier-node {
        min-width: auto;
        width: 100%;
        padding: var(--spacing-md);
    }

    .tier-node-emoji {
        font-size: 2rem;
    }

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

    /* Topic Page */
    .topic-sidebar {
        display: none;
        position: fixed;
        left: 0;
        top: 80px;
        bottom: 0;
        width: 100%;
        max-width: 300px;
        transform: translateX(-100%);
        transition: transform var(--transition-normal);
    }

    .topic-sidebar.active {
        display: block;
        transform: translateX(0);
    }

    .topic-content {
        margin-left: 0;
        padding: var(--spacing-md);
    }

    .topic-title {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-sm);
    }
}

@media (max-width: 480px) {
    html {
        font-size: 14px;
    }

    .hero-logo {
        font-size: 4rem;
    }

    .navbar {
        padding: var(--spacing-sm);
    }

    .path-node {
        padding: var(--spacing-sm) var(--spacing-md);
    }
}

/* ---------- Scrollbar ---------- */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background: var(--text-muted);
}

/* ---------- Selection ---------- */
::selection {
    background: rgba(0, 229, 255, 0.3);
    color: var(--text-primary);
}

/* ---------- Focus States ---------- */
a:focus-visible,
button:focus-visible {
    outline: 2px solid var(--accent-cyan);
    outline-offset: 2px;
}

/* ---------- Reduced Motion ---------- */
@media (prefers-reduced-motion: reduce) {

    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}