/* ============================================
    ML VISUALIZED — MAIN STYLES
   Dark, modern, interactive learning platform
   ============================================ */

:root {
    --bg: #08090f;
    --bg-card: #0f1120;
    --bg-card2: #131629;
    --border: rgba(255,255,255,0.07);
    --border-hover: rgba(108,99,255,0.5);
    --accent: #6c63ff;
    --accent2: #3ecfda;
    --accent3: #f7666f;
    --green: #22c55e;
    --text: #e8eaf0;
    --text-muted: #7c8099;
    --text-dim: #4a4f6a;
    --font: 'Inter', sans-serif;
    --font-mono: 'JetBrains Mono', monospace;
    --font-display: 'Space Grotesk', sans-serif;
    --radius: 16px;
    --radius-sm: 10px;
    --shadow: 0 0 40px rgba(108,99,255,0.15);
    --glow: 0 0 60px rgba(108,99,255,0.25);
}

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

html { scroll-behavior: smooth; }

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

/* === Background Canvas === */
#bg-canvas {
    position: fixed;
    top: 0; left: 0;
    width: 100%; height: 100%;
    z-index: 0;
    pointer-events: none;
    opacity: 0.35;
}

/* === Navigation === */
.navbar {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 100;
    padding: 16px 40px;
    transition: all 0.3s ease;
}

.navbar.scrolled {
    background: rgba(8, 9, 15, 0.9);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}

.nav-inner {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--text);
}

.brand-icon {
    font-size: 1.5rem;
    color: var(--accent);
    filter: drop-shadow(0 0 8px var(--accent));
}

.brand-text {
    font-family: var(--font-display);
    font-size: 1.2rem;
    font-weight: 700;
    letter-spacing: -0.5px;
}

.brand-accent { color: var(--accent); }

.nav-links {
    display: flex;
    list-style: none;
    gap: 32px;
    align-items: center;
}

.nav-links a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    transition: color 0.2s;
}

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

.nav-cta {
    background: var(--accent) !important;
    color: white !important;
    padding: 8px 20px;
    border-radius: 8px;
    font-weight: 600 !important;
    transition: all 0.2s !important;
}

.nav-cta:hover {
    background: #7d75ff !important;
    box-shadow: 0 0 20px rgba(108,99,255,0.4);
}

/* === Container === */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px;
    position: relative;
    z-index: 1;
}

/* === Hero === */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 40px 80px;
    max-width: 1200px;
    margin: 0 auto;
    gap: 60px;
    position: relative;
    z-index: 1;
}

/* === Premium Landing Page === */
.premium-hero {
    padding: 140px 0 70px;
    position: relative;
    z-index: 1;
}

.premium-hero-grid {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 28px;
    align-items: center;
}

.premium-title {
    font-family: var(--font-display);
    font-size: clamp(2rem, 4vw, 3.2rem);
    line-height: 1.15;
    letter-spacing: -1px;
    margin-bottom: 16px;
}

.premium-lead {
    color: var(--text-muted);
    font-size: 1rem;
    line-height: 1.75;
    margin-bottom: 30px;
    max-width: 660px;
}

.premium-proof {
    margin-top: 18px;
    font-size: 0.86rem;
    color: var(--accent2);
}

.premium-signal-card {
    border: 1px solid var(--border);
    background: linear-gradient(160deg, rgba(255,255,255,0.04), rgba(108,99,255,0.07));
    border-radius: 18px;
    padding: 24px;
}

.premium-signal-card h3 {
    font-family: var(--font-display);
    font-size: 1.2rem;
    margin-bottom: 14px;
}

.premium-signal-card ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 10px;
    margin-bottom: 18px;
}

.premium-signal-card li {
    font-size: 0.9rem;
    color: var(--text-muted);
    padding-left: 16px;
    position: relative;
}

.premium-signal-card li::before {
    content: '•';
    color: var(--accent);
    position: absolute;
    left: 0;
}

.premium-signal-metric {
    border-top: 1px solid var(--border);
    padding-top: 14px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.premium-signal-metric span {
    color: var(--text-muted);
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.8px;
}

.premium-signal-metric strong {
    color: var(--text);
    font-size: 1rem;
}

.plans-section {
    padding: 36px 0 90px;
    position: relative;
    z-index: 1;
}

.plans-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 18px;
}

.plan-card {
    border: 1px solid var(--border);
    border-radius: 16px;
    background: var(--bg-card);
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
    position: relative;
}

.plan-card h3 {
    font-family: var(--font-display);
    font-size: 1.3rem;
}

.plan-price {
    font-family: var(--font-display);
    font-size: 2rem;
    font-weight: 800;
    line-height: 1;
}

.plan-price span {
    font-family: var(--font);
    font-size: 0.9rem;
    color: var(--text-muted);
    font-weight: 500;
}

.plan-card ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
    min-height: 128px;
}

.plan-card li {
    color: var(--text-muted);
    font-size: 0.9rem;
    padding-left: 15px;
    position: relative;
}

.plan-card li::before {
    content: '✓';
    color: var(--green);
    position: absolute;
    left: 0;
}

.featured-plan {
    border-color: rgba(108,99,255,0.5);
    box-shadow: 0 18px 36px rgba(108,99,255,0.14);
}

.hero-content { flex: 1; }

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(108,99,255,0.12);
    border: 1px solid rgba(108,99,255,0.3);
    color: var(--accent);
    padding: 6px 16px;
    border-radius: 100px;
    font-size: 0.8rem;
    font-weight: 500;
    margin-bottom: 28px;
    letter-spacing: 0.3px;
}

.badge-dot {
    width: 6px; height: 6px;
    background: var(--accent);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--accent);
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(0.8); }
}

.hero-title {
    font-family: var(--font-display);
    font-size: clamp(2.8rem, 5vw, 4.5rem);
    font-weight: 800;
    line-height: 1.1;
    letter-spacing: -2px;
    margin-bottom: 20px;
}

.gradient-text {
    background: linear-gradient(135deg, var(--accent) 0%, var(--accent2) 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-desc {
    font-size: 1.1rem;
    color: var(--text-muted);
    max-width: 520px;
    margin-bottom: 36px;
    line-height: 1.7;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 48px;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 14px 28px;
    border-radius: 10px;
    font-size: 0.95rem;
    font-weight: 600;
    text-decoration: none;
    transition: all 0.25s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 24px rgba(108,99,255,0.4);
}

.btn-primary:hover {
    background: #7d75ff;
    box-shadow: 0 4px 32px rgba(108,99,255,0.6);
    transform: translateY(-2px);
}

.btn-ghost {
    background: rgba(255,255,255,0.06);
    color: var(--text);
    border: 1px solid var(--border);
}

.btn-ghost:hover {
    background: rgba(255,255,255,0.1);
    border-color: rgba(255,255,255,0.15);
}

.hero-stats {
    display: flex;
    align-items: center;
    gap: 24px;
}

.stat { text-align: center; }

.stat-num {
    display: block;
    font-family: var(--font-display);
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--text);
    line-height: 1;
}

.stat-label {
    font-size: 0.78rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.stat-divider {
    width: 1px;
    height: 36px;
    background: var(--border);
}

/* Hero Visual */
.hero-visual {
    flex: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    max-width: 500px;
}

#hero-network {
    border-radius: 20px;
    background: rgba(255,255,255,0.02);
    border: 1px solid var(--border);
}

.hero-float-cards {
    position: absolute;
    inset: 0;
    pointer-events: none;
}

.float-card {
    position: absolute;
    background: rgba(15,17,32,0.9);
    border: 1px solid var(--border);
    border-radius: 12px;
    padding: 12px 16px;
    min-width: 150px;
    backdrop-filter: blur(20px);
    animation: floatCard 4s ease-in-out infinite;
}

.float-card:nth-child(2) { animation-delay: 1.5s; }
.float-card:nth-child(3) { animation-delay: 3s; }

@keyframes floatCard {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-8px); }
}

.fc-label {
    display: block;
    font-size: 0.7rem;
    color: var(--text-muted);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 4px;
}

.fc-value {
    display: block;
    font-family: var(--font-mono);
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 8px;
}

.fc-bar {
    height: 4px;
    background: rgba(255,255,255,0.1);
    border-radius: 2px;
    overflow: hidden;
}

.fc-bar-fill {
    height: 100%;
    background: var(--accent);
    border-radius: 2px;
    transition: width 1s ease;
}

.fc-bar-fill.green { background: var(--green); }
.fc-bar-fill.blue { background: var(--accent2); }

/* === Premium CTA Section === */
.premium-section {
    padding: 24px 0 80px;
    position: relative;
    z-index: 1;
}

.premium-card {
    display: grid;
    grid-template-columns: 1.2fr 0.8fr;
    gap: 32px;
    border: 1px solid rgba(108,99,255,0.3);
    border-radius: 20px;
    padding: 36px;
    background:
        radial-gradient(circle at top left, rgba(108,99,255,0.16), transparent 52%),
        radial-gradient(circle at bottom right, rgba(62,207,218,0.14), transparent 46%),
        var(--bg-card);
    box-shadow: 0 18px 40px rgba(0,0,0,0.28);
}

.premium-copy h2 {
    font-family: var(--font-display);
    font-size: clamp(1.5rem, 2.5vw, 2.3rem);
    letter-spacing: -0.5px;
    line-height: 1.2;
    margin-bottom: 14px;
}

.premium-copy p {
    color: var(--text-muted);
    font-size: 1rem;
    margin-bottom: 18px;
    max-width: 640px;
}

.premium-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.premium-list li {
    color: var(--text);
    font-size: 0.92rem;
    position: relative;
    padding-left: 18px;
}

.premium-list li::before {
    content: '▹';
    color: var(--accent2);
    position: absolute;
    left: 0;
}

.premium-form-wrap {
    background: rgba(8,9,15,0.72);
    border: 1px solid var(--border);
    border-radius: 14px;
    padding: 20px;
    backdrop-filter: blur(8px);
}

.premium-form {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.premium-form label {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.8px;
    color: var(--text-muted);
}

.premium-form input {
    width: 100%;
    border: 1px solid var(--border);
    background: rgba(255,255,255,0.04);
    color: var(--text);
    border-radius: 10px;
    padding: 12px 14px;
    font-size: 0.92rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.premium-form select {
    width: 100%;
    border: 1px solid var(--border);
    background: rgba(255,255,255,0.04);
    color: var(--text);
    border-radius: 10px;
    padding: 12px 14px;
    font-size: 0.92rem;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.premium-form select:focus {
    border-color: rgba(62,207,218,0.8);
    box-shadow: 0 0 0 3px rgba(62,207,218,0.15);
}

.premium-form input:focus {
    border-color: rgba(62,207,218,0.8);
    box-shadow: 0 0 0 3px rgba(62,207,218,0.15);
}

.premium-submit {
    margin-top: 6px;
    width: 100%;
    justify-content: center;
}

.premium-meta {
    margin-top: 2px;
    color: var(--text-dim);
    font-size: 0.78rem;
    line-height: 1.5;
}

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* === Chapters Section === */
.chapters-section {
    padding: 120px 0;
    position: relative;
    z-index: 1;
}

.section-header {
    text-align: center;
    margin-bottom: 64px;
}

.section-tag {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 2px;
    color: var(--accent);
    text-transform: uppercase;
    margin-bottom: 12px;
}

.section-header h2 {
    font-family: var(--font-display);
    font-size: clamp(1.8rem, 3vw, 2.8rem);
    font-weight: 800;
    letter-spacing: -1px;
    margin-bottom: 12px;
}

.section-header p {
    color: var(--text-muted);
    font-size: 1.05rem;
}

/* Chapters Grid */
.chapters-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.chapter-card {
    position: relative;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    text-decoration: none;
    color: var(--text);
    transition: all 0.3s ease;
    display: flex;
    flex-direction: column;
}

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

.chapter-card.featured {
    border-color: rgba(62,207,218,0.2);
}

.chapter-card.featured:hover {
    border-color: rgba(62,207,218,0.5);
    box-shadow: 0 0 40px rgba(62,207,218,0.15);
}

.chapter-num {
    position: absolute;
    top: 16px;
    right: 20px;
    font-family: var(--font-display);
    font-size: 2.5rem;
    font-weight: 900;
    color: rgba(255,255,255,0.04);
    line-height: 1;
    z-index: 0;
}

.featured-badge {
    position: absolute;
    top: 16px;
    left: 16px;
    background: linear-gradient(135deg, var(--accent2), #22c55e);
    color: #000;
    font-size: 0.65rem;
    font-weight: 800;
    letter-spacing: 1px;
    padding: 4px 10px;
    border-radius: 100px;
    z-index: 1;
}

.chapter-canvas-wrap {
    height: 180px;
    background: linear-gradient(180deg, rgba(108,99,255,0.05) 0%, transparent 100%);
    overflow: hidden;
    border-bottom: 1px solid var(--border);
}

.chapter-preview {
    width: 100%;
    height: 100%;
    display: block;
}

.chapter-body {
    padding: 24px;
    flex: 1;
}

.chapter-tag {
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 1px;
    text-transform: uppercase;
    color: var(--accent);
    margin-bottom: 8px;
}

.chapter-body h3 {
    font-family: var(--font-display);
    font-size: 1.3rem;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.3px;
}

.chapter-body p {
    font-size: 0.88rem;
    color: var(--text-muted);
    line-height: 1.6;
    margin-bottom: 16px;
}

.chapter-topics {
    list-style: none;
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.chapter-topics li {
    font-size: 0.75rem;
    color: var(--text-dim);
    background: rgba(255,255,255,0.05);
    padding: 4px 10px;
    border-radius: 100px;
    border: 1px solid var(--border);
}

.chapter-footer {
    padding: 16px 24px;
    border-top: 1px solid var(--border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 0.82rem;
    color: var(--text-muted);
}

.arrow-link {
    color: var(--accent);
    font-weight: 600;
    transition: gap 0.2s;
}

.chapter-card:hover .arrow-link { letter-spacing: 0.5px; }

/* === Algorithm Table === */
.algorithms-section {
    padding: 100px 0;
    position: relative;
    z-index: 1;
}

.algo-table-wrap {
    overflow-x: auto;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    background: var(--bg-card);
}

.algo-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.88rem;
}

.algo-table thead tr {
    background: rgba(255,255,255,0.03);
    border-bottom: 1px solid var(--border);
}

.algo-table th {
    padding: 14px 20px;
    text-align: left;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    font-weight: 600;
}

.algo-table td {
    padding: 14px 20px;
    border-bottom: 1px solid var(--border);
    color: var(--text-muted);
}

.algo-table tr:last-child td { border-bottom: none; }

.algo-table tr:hover td {
    background: rgba(108,99,255,0.05);
    color: var(--text);
}

.algo-table a {
    color: var(--text);
    text-decoration: none;
    font-weight: 500;
}

.algo-table a:hover { color: var(--accent); }

.mono { font-family: var(--font-mono); font-size: 0.82rem; }

.tag {
    display: inline-block;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.5px;
    padding: 3px 10px;
    border-radius: 100px;
}

.tag.opt { background: rgba(108,99,255,0.15); color: #9d98ff; }
.tag.unsup { background: rgba(62,207,218,0.12); color: #3ecfda; }
.tag.sup { background: rgba(247,102,111,0.12); color: #f9888f; }
.tag.deep { background: rgba(250,173,20,0.12); color: #faad14; }
.tag.gen { background: rgba(34,197,94,0.12); color: #22c55e; }

/* === About Section === */
.about-section {
    padding: 100px 0;
    position: relative;
    z-index: 1;
}

.about-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 80px;
    align-items: start;
}

.about-text .section-tag { display: block; margin-bottom: 12px; }

.about-text h2 {
    font-family: var(--font-display);
    font-size: clamp(1.6rem, 2.5vw, 2.4rem);
    font-weight: 800;
    letter-spacing: -0.5px;
    margin-bottom: 20px;
    line-height: 1.2;
}

.about-text p {
    color: var(--text-muted);
    margin-bottom: 16px;
    font-size: 0.98rem;
    line-height: 1.7;
}

.about-refs {
    margin-top: 32px;
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
}

.about-refs h4 {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 14px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.about-refs ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.about-refs li {
    font-size: 0.82rem;
    color: var(--text-muted);
    padding-left: 16px;
    position: relative;
}

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

/* Paper Cards */
.paper-cards {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.paper-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 20px;
    transition: all 0.25s ease;
}

.paper-card:hover {
    border-color: var(--border-hover);
    transform: translateX(4px);
}

.paper-card.highlighted {
    border-color: rgba(62,207,218,0.3);
    background: rgba(62,207,218,0.05);
}

.paper-year {
    font-size: 0.72rem;
    font-weight: 700;
    color: var(--accent);
    letter-spacing: 0.5px;
    margin-bottom: 6px;
}

.paper-title {
    font-weight: 600;
    font-size: 0.92rem;
    margin-bottom: 4px;
}

.paper-authors {
    font-size: 0.78rem;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.paper-impact {
    font-size: 0.75rem;
    color: var(--accent2);
}

/* === Footer === */
.footer {
    padding: 60px 0 30px;
    border-top: 1px solid var(--border);
    position: relative;
    z-index: 1;
}

.footer-inner {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-brand .brand-icon {
    font-size: 1.4rem;
}

.footer-brand p {
    font-size: 0.85rem;
    color: var(--text-muted);
    margin-top: 10px;
    max-width: 260px;
}

.footer-links-group h4 {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.footer-links-group ul { list-style: none; }
.footer-links-group li { margin-bottom: 10px; }

.footer-links-group a {
    color: var(--text-muted);
    text-decoration: none;
    font-size: 0.88rem;
    transition: color 0.2s;
}

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

.footer-bottom {
    border-top: 1px solid var(--border);
    padding-top: 20px;
    text-align: center;
    font-size: 0.8rem;
    color: var(--text-dim);
}

.nav-hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
    margin-left: 8px;
}

.nav-hamburger span {
    display: block;
    width: 22px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: all 0.3s;
}

/* Mobile nav overlay */
.nav-mobile {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(8,9,15,0.97);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    z-index: 200;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 40px;
    text-align: center;
}

.nav-mobile.open { display: flex; }

.nav-mobile ul {
    list-style: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 28px;
}

.nav-mobile ul a {
    font-family: var(--font-display);
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--text);
    text-decoration: none;
    transition: color 0.2s;
}

.nav-mobile ul a:hover { color: var(--accent); }

.nav-mobile-close {
    position: absolute;
    top: 24px;
    right: 28px;
    background: none;
    border: none;
    font-size: 1.6rem;
    color: var(--text-muted);
    cursor: pointer;
    transition: color 0.2s;
    line-height: 1;
}

.nav-mobile-close:hover { color: var(--text); }

/* === Scrollbar === */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: var(--bg); }
::-webkit-scrollbar-thumb { background: rgba(108,99,255,0.4); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: rgba(108,99,255,0.7); }

/* === Responsive === */
@media (max-width: 1024px) {
    .premium-hero-grid { grid-template-columns: 1fr; }
    .plans-grid { grid-template-columns: 1fr; }
    .premium-card { grid-template-columns: 1fr; }
    .chapters-grid { grid-template-columns: repeat(2, 1fr); }
    .about-grid { grid-template-columns: 1fr; gap: 40px; }
}

@media (max-width: 768px) {
    .premium-section { padding: 16px 0 64px; }
    .premium-card { padding: 24px; }
    .hero { flex-direction: column; padding: 100px 20px 60px; }
    .hero-visual { display: none; }
    .chapters-grid { grid-template-columns: 1fr; }
    .container { padding: 0 20px; }
    .navbar { padding: 16px 20px; }
    .nav-links { display: none; }
    .nav-hamburger { display: flex; }
    .footer-inner { grid-template-columns: 1fr; gap: 30px; }
}