/* ===================================================================
   OperAI Playbook — Design System
   ===================================================================

   Typography: Instrument Serif (display) + Inter (body) + JetBrains Mono (code)
   Colors: Navy #0B1221 bg, Gold #C9A04A accent, off-white text
   Layout: 3-column desktop, 2-column tablet, single mobile
*/

:root {
    /* Colors */
    --bg: #0B1221;
    --bg-elevated: #111B2E;
    --bg-hover: rgba(255, 255, 255, 0.04);
    --surface: #1A2540;
    --border: rgba(255, 255, 255, 0.07);
    --border-strong: rgba(255, 255, 255, 0.15);

    --text: #FAF9F6;
    --text-dim: rgba(255, 255, 255, 0.55);
    --text-muted: rgba(255, 255, 255, 0.35);
    --text-faint: rgba(255, 255, 255, 0.2);

    --gold: #C9A04A;
    --gold-light: #D4AD5A;
    --gold-dim: rgba(201, 160, 74, 0.1);
    --gold-glow: rgba(201, 160, 74, 0.3);

    --green: #22C55E;
    --red: #EF4444;
    --yellow: #EAB308;
    --blue: #60A5FA;

    /* Typography */
    --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --font-serif: 'Instrument Serif', Georgia, 'Times New Roman', serif;
    --font-mono: 'JetBrains Mono', 'SF Mono', Menlo, Consolas, monospace;

    /* Layout */
    --sidebar-width: 280px;
    --toc-width: 240px;
    --content-max: 720px;
    --header-height: 60px;

    /* Misc */
    --radius: 8px;
    --radius-lg: 12px;
    --transition: 0.15s ease;
}

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

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    background: var(--bg);
    color: var(--text);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.7;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
    overflow-x: hidden;
}

/* ===== READING PROGRESS BAR ===== */
#progress-bar {
    position: fixed;
    top: 0;
    left: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--gold), var(--gold-light));
    width: 0;
    z-index: 1000;
    transition: width 0.1s ease;
    box-shadow: 0 0 10px var(--gold-glow);
}

/* ===== HEADER ===== */
.header {
    position: sticky;
    top: 0;
    background: rgba(11, 18, 33, 0.85);
    backdrop-filter: saturate(180%) blur(12px);
    -webkit-backdrop-filter: saturate(180%) blur(12px);
    border-bottom: 1px solid var(--border);
    z-index: 100;
    height: var(--header-height);
}

.header-inner {
    max-width: 1440px;
    margin: 0 auto;
    padding: 0 1.5rem;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.logo {
    font-weight: 700;
    font-size: 1.1rem;
    letter-spacing: -0.03em;
    color: var(--text);
    text-decoration: none;
}

.logo b {
    color: var(--gold);
}

.header-tag {
    font-size: 0.7rem;
    font-weight: 500;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--gold);
    background: var(--gold-dim);
    padding: 0.3rem 0.65rem;
    border-radius: 4px;
    border: 1px solid rgba(201, 160, 74, 0.2);
}

.header-right {
    display: flex;
    align-items: center;
    gap: 1.25rem;
}

.header-right a {
    color: var(--text-dim);
    text-decoration: none;
    font-size: 0.85rem;
    transition: color var(--transition);
}

.header-right a:hover {
    color: var(--text);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: var(--text);
    font-size: 1.4rem;
    cursor: pointer;
    padding: 0.25rem 0.5rem;
}

/* ===== LAYOUT ===== */
.layout {
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr var(--toc-width);
    max-width: 1440px;
    margin: 0 auto;
    gap: 0;
}

/* ===== SIDEBAR ===== */
.sidebar {
    position: sticky;
    top: var(--header-height);
    height: calc(100vh - var(--header-height));
    overflow-y: auto;
    padding: 2rem 1.5rem 2rem 1.5rem;
    border-right: 1px solid var(--border);
}

.sidebar::-webkit-scrollbar {
    width: 4px;
}

.sidebar::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 2px;
}

.sidebar-section {
    margin-bottom: 1.5rem;
}

.sidebar-section-title {
    font-size: 0.62rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--text-muted);
    padding: 0.5rem 0.75rem 0.6rem;
    margin-bottom: 0.25rem;
}

.sidebar-link {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 0.75rem;
    border-radius: 6px;
    font-size: 0.85rem;
    color: var(--text-dim);
    text-decoration: none;
    line-height: 1.45;
    transition: all var(--transition);
    position: relative;
}

.sidebar-link:hover {
    color: var(--text);
    background: var(--bg-hover);
}

.sidebar-link.active {
    color: var(--gold);
    background: var(--gold-dim);
    font-weight: 500;
}

.sidebar-link.active::before {
    content: '';
    position: absolute;
    left: -1.5rem;
    top: 50%;
    transform: translateY(-50%);
    width: 3px;
    height: 60%;
    background: var(--gold);
    border-radius: 0 2px 2px 0;
}

.sidebar-num {
    font-family: var(--font-mono);
    font-size: 0.68rem;
    color: var(--text-faint);
    min-width: 22px;
    flex-shrink: 0;
}

.sidebar-link.active .sidebar-num {
    color: var(--gold);
}

/* ===== CONTENT ===== */
.content {
    padding: 3rem 3rem 6rem;
    min-width: 0;
    overflow-x: hidden;
}

.content-inner {
    max-width: var(--content-max);
    margin: 0 auto;
}

/* Chapter meta (reading time, chapter number) */
.chapter-meta {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--text-muted);
}

.chapter-meta .dot {
    width: 3px;
    height: 3px;
    background: var(--text-faint);
    border-radius: 50%;
}

.chapter-meta .chapter-num {
    color: var(--gold);
}

/* ===== TYPOGRAPHY ===== */
.content h1 {
    font-family: var(--font-serif);
    font-size: 3.2rem;
    font-weight: 400;
    line-height: 1.05;
    letter-spacing: -0.02em;
    margin-bottom: 1.5rem;
    color: var(--text);
}

.content h1 em {
    font-style: italic;
    color: var(--gold);
}

.content h2 {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 400;
    line-height: 1.15;
    letter-spacing: -0.015em;
    margin: 3.5rem 0 1rem;
    color: var(--text);
    scroll-margin-top: calc(var(--header-height) + 2rem);
}

.content h2 em {
    font-style: italic;
    color: var(--gold);
}

.content h3 {
    font-family: var(--font-sans);
    font-size: 1.25rem;
    font-weight: 600;
    line-height: 1.3;
    letter-spacing: -0.01em;
    margin: 2.5rem 0 0.75rem;
    color: var(--text);
    scroll-margin-top: calc(var(--header-height) + 2rem);
}

.content h4 {
    font-family: var(--font-sans);
    font-size: 1rem;
    font-weight: 600;
    margin: 2rem 0 0.5rem;
    color: var(--text);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}

.content p {
    margin-bottom: 1.25rem;
    font-size: 1.02rem;
    line-height: 1.75;
    color: rgba(255, 255, 255, 0.78);
}

.content p:first-of-type {
    font-size: 1.1rem;
    color: var(--text);
    line-height: 1.7;
}

.content strong {
    color: var(--text);
    font-weight: 600;
}

.content em {
    color: var(--text);
    font-style: italic;
}

.content a {
    color: var(--gold);
    text-decoration: none;
    border-bottom: 1px solid rgba(201, 160, 74, 0.35);
    transition: border-color var(--transition);
}

.content a:hover {
    border-bottom-color: var(--gold);
}

/* ===== LISTS ===== */
.content ul,
.content ol {
    margin: 0.75rem 0 1.5rem 0;
    padding-left: 1.5rem;
    color: rgba(255, 255, 255, 0.78);
}

.content li {
    margin-bottom: 0.5rem;
    line-height: 1.7;
}

.content li::marker {
    color: var(--gold);
}

.content ul ul,
.content ol ol,
.content ul ol,
.content ol ul {
    margin: 0.5rem 0;
}

/* ===== BLOCKQUOTES ===== */
.content blockquote {
    border-left: 3px solid var(--gold);
    padding: 1rem 1.25rem;
    margin: 1.75rem 0;
    background: var(--gold-dim);
    border-radius: 0 8px 8px 0;
    color: var(--text);
}

.content blockquote p {
    margin-bottom: 0.5rem;
}

.content blockquote p:last-child {
    margin-bottom: 0;
}

.content blockquote strong {
    color: var(--gold);
}

/* ===== CODE ===== */
.content code {
    font-family: var(--font-mono);
    font-size: 0.85em;
    background: var(--bg-elevated);
    padding: 0.15em 0.4em;
    border-radius: 4px;
    color: var(--gold);
    border: 1px solid var(--border);
    white-space: nowrap;
}

.content pre {
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem 1.5rem;
    overflow-x: auto;
    margin: 1.5rem 0;
    font-family: var(--font-mono);
    font-size: 0.85rem;
    line-height: 1.6;
    position: relative;
}

.content pre::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--gold), transparent);
    border-radius: var(--radius) var(--radius) 0 0;
}

.content pre code {
    background: none;
    border: none;
    padding: 0;
    color: var(--text);
    white-space: pre;
    font-size: inherit;
}

/* Code syntax colors (Prism.js-compatible) */
.content pre .token.comment { color: var(--text-muted); font-style: italic; }
.content pre .token.string { color: #A3E635; }
.content pre .token.number { color: #F59E0B; }
.content pre .token.keyword { color: #A78BFA; }
.content pre .token.function { color: var(--gold); }
.content pre .token.operator { color: var(--text-dim); }
.content pre .token.punctuation { color: var(--text-dim); }
.content pre .token.property { color: #60A5FA; }
.content pre .token.boolean { color: #F472B6; }

/* ===== TABLES ===== */
.content table {
    width: 100%;
    border-collapse: collapse;
    margin: 1.5rem 0;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    font-size: 0.88rem;
}

.content table th {
    background: rgba(201, 160, 74, 0.06);
    color: var(--gold);
    font-weight: 600;
    text-align: left;
    padding: 0.75rem 1rem;
    font-size: 0.7rem;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    border-bottom: 1px solid var(--border);
}

.content table td {
    padding: 0.75rem 1rem;
    border-bottom: 1px solid rgba(255, 255, 255, 0.03);
    color: rgba(255, 255, 255, 0.78);
    vertical-align: top;
}

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

.content table tr:hover td {
    background: rgba(255, 255, 255, 0.02);
}

.content table td:first-child {
    color: var(--text);
    font-weight: 500;
}

.content table strong {
    color: var(--gold);
}

/* ===== HR ===== */
.content hr {
    border: none;
    height: 1px;
    background: var(--border);
    margin: 3rem 0;
    position: relative;
}

.content hr::after {
    content: '✦';
    position: absolute;
    left: 50%;
    top: -0.5rem;
    transform: translateX(-50%);
    background: var(--bg);
    padding: 0 1rem;
    color: var(--gold);
    font-size: 0.8rem;
}

/* ===== IMAGES ===== */
.content img {
    max-width: 100%;
    border-radius: var(--radius);
    margin: 1.5rem 0;
}

/* ===== TOC (RIGHT SIDEBAR) ===== */
.toc {
    position: sticky;
    top: var(--header-height);
    height: calc(100vh - var(--header-height));
    overflow-y: auto;
    padding: 3rem 1.5rem 2rem;
    border-left: 1px solid var(--border);
    font-size: 0.82rem;
}

.toc::-webkit-scrollbar {
    width: 4px;
}

.toc::-webkit-scrollbar-thumb {
    background: rgba(255, 255, 255, 0.1);
    border-radius: 2px;
}

.toc-title {
    font-size: 0.62rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--text-muted);
    margin-bottom: 0.75rem;
}

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

.toc li {
    margin-bottom: 0.1rem;
    line-height: 1.4;
}

.toc a {
    display: block;
    padding: 0.3rem 0 0.3rem 0.75rem;
    color: var(--text-dim);
    text-decoration: none;
    border-left: 2px solid transparent;
    transition: all var(--transition);
    font-size: 0.8rem;
}

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

.toc a.active {
    color: var(--gold);
    border-left-color: var(--gold);
}

.toc li.toc-h3 a {
    padding-left: 1.5rem;
    font-size: 0.75rem;
    color: var(--text-muted);
}

/* ===== CHAPTER NAVIGATION ===== */
.chapter-nav {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1rem;
    margin: 4rem 0 2rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border);
}

.chapter-nav a {
    display: flex;
    flex-direction: column;
    gap: 0.25rem;
    padding: 1rem 1.25rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-decoration: none;
    transition: all var(--transition);
}

.chapter-nav a:hover {
    border-color: var(--gold);
    background: var(--surface);
    transform: translateY(-2px);
}

.chapter-nav a.next {
    text-align: right;
}

.chapter-nav .nav-label {
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-muted);
}

.chapter-nav .nav-title {
    font-size: 1rem;
    color: var(--text);
    font-weight: 500;
}

.chapter-nav a.prev .nav-title::before {
    content: '← ';
    color: var(--gold);
}

.chapter-nav a.next .nav-title::after {
    content: ' →';
    color: var(--gold);
}

/* ===================================================================
   LANDING PAGE (index.html) — Hero + TOC
   =================================================================== */

.landing {
    min-height: calc(100vh - var(--header-height));
}

.hero {
    max-width: 880px;
    margin: 0 auto;
    padding: 6rem 2rem 4rem;
    text-align: center;
}

.hero-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 0.7rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--gold);
    background: var(--gold-dim);
    padding: 0.4rem 0.85rem;
    border-radius: 100px;
    border: 1px solid rgba(201, 160, 74, 0.2);
    margin-bottom: 2rem;
}

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

@keyframes pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

.hero h1 {
    font-family: var(--font-serif);
    font-size: 4rem;
    font-weight: 400;
    line-height: 1.02;
    letter-spacing: -0.025em;
    margin-bottom: 1.25rem;
    color: var(--text);
}

.hero h1 em {
    font-style: italic;
    color: var(--gold);
}

.hero-subtitle {
    font-family: var(--font-sans);
    font-size: 1.35rem;
    line-height: 1.5;
    color: var(--text-dim);
    max-width: 640px;
    margin: 0 auto 1.25rem;
    font-weight: 400;
}

.hero-description {
    font-size: 1rem;
    line-height: 1.7;
    color: var(--text-muted);
    max-width: 580px;
    margin: 0 auto 2.5rem;
}

.hero-cta {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 3rem;
}

.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.85rem 1.5rem;
    border-radius: var(--radius);
    font-family: var(--font-sans);
    font-size: 0.95rem;
    font-weight: 500;
    text-decoration: none;
    transition: all var(--transition);
    cursor: pointer;
    border: 1px solid transparent;
}

.btn-primary {
    background: linear-gradient(135deg, var(--gold), #A8842E);
    color: var(--bg);
    font-weight: 600;
    box-shadow: 0 4px 20px rgba(201, 160, 74, 0.25);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 24px rgba(201, 160, 74, 0.4);
}

.btn-secondary {
    background: var(--bg-elevated);
    color: var(--text);
    border-color: var(--border);
}

.btn-secondary:hover {
    border-color: var(--border-strong);
    background: var(--surface);
}

/* Hero stats */
.hero-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 2rem;
    max-width: 720px;
    margin: 3rem auto 0;
    padding: 2rem 0;
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.hero-stat {
    text-align: center;
}

.hero-stat-value {
    font-family: var(--font-serif);
    font-size: 2.2rem;
    color: var(--gold);
    line-height: 1;
    margin-bottom: 0.3rem;
}

.hero-stat-label {
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--text-muted);
}

/* Landing TOC */
.landing-toc {
    max-width: 880px;
    margin: 4rem auto;
    padding: 0 2rem;
}

.landing-toc-title {
    font-family: var(--font-serif);
    font-size: 2rem;
    font-weight: 400;
    text-align: center;
    margin-bottom: 3rem;
    color: var(--text);
}

.landing-toc-title em {
    font-style: italic;
    color: var(--gold);
}

.landing-section {
    margin-bottom: 3rem;
}

.landing-section-header {
    display: flex;
    align-items: baseline;
    gap: 0.75rem;
    margin-bottom: 1.25rem;
    padding-bottom: 0.75rem;
    border-bottom: 1px solid var(--border);
}

.landing-section-number {
    font-family: var(--font-serif);
    font-size: 1.5rem;
    color: var(--gold);
    font-style: italic;
}

.landing-section-title {
    font-family: var(--font-sans);
    font-size: 0.7rem;
    font-weight: 700;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--text-muted);
}

.landing-chapters {
    display: grid;
    gap: 0.5rem;
}

.landing-chapter {
    display: flex;
    align-items: center;
    gap: 1rem;
    padding: 1rem 1.25rem;
    background: var(--bg-elevated);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    text-decoration: none;
    transition: all var(--transition);
}

.landing-chapter:hover {
    border-color: var(--gold);
    background: var(--surface);
    transform: translateX(4px);
}

.landing-chapter-num {
    font-family: var(--font-mono);
    font-size: 0.75rem;
    color: var(--gold);
    min-width: 32px;
    flex-shrink: 0;
}

.landing-chapter-content {
    flex: 1;
    min-width: 0;
}

.landing-chapter-title {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text);
    margin-bottom: 0.2rem;
}

.landing-chapter-desc {
    font-size: 0.82rem;
    color: var(--text-muted);
    line-height: 1.5;
}

.landing-chapter-time {
    font-family: var(--font-mono);
    font-size: 0.7rem;
    color: var(--text-faint);
    flex-shrink: 0;
    white-space: nowrap;
}

.landing-chapter-arrow {
    color: var(--text-faint);
    transition: color var(--transition), transform var(--transition);
    flex-shrink: 0;
}

.landing-chapter:hover .landing-chapter-arrow {
    color: var(--gold);
    transform: translateX(2px);
}

/* Landing footer */
.landing-footer {
    max-width: 640px;
    margin: 4rem auto 3rem;
    padding: 2rem;
    text-align: center;
    border-top: 1px solid var(--border);
    color: var(--text-muted);
    font-size: 0.85rem;
}

.landing-footer a {
    color: var(--gold);
    text-decoration: none;
}

/* ===== FOOTER (chapter pages) ===== */
.footer {
    padding: 1.5rem 2rem;
    border-top: 1px solid var(--border);
    font-size: 0.78rem;
    color: var(--text-muted);
    text-align: center;
}

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

/* ===================================================================
   RESPONSIVE
   =================================================================== */

/* Tablet — hide TOC right sidebar */
@media (max-width: 1200px) {
    .layout {
        grid-template-columns: var(--sidebar-width) 1fr;
    }
    .toc {
        display: none;
    }
    .content {
        padding: 3rem 2.5rem 6rem;
    }
}

/* Small tablet — narrower sidebar */
@media (max-width: 960px) {
    :root {
        --sidebar-width: 240px;
    }
    .content {
        padding: 2.5rem 2rem 5rem;
    }
    .content h1 {
        font-size: 2.6rem;
    }
    .content h2 {
        font-size: 1.75rem;
    }
    .hero h1 {
        font-size: 3rem;
    }
    .hero-subtitle {
        font-size: 1.15rem;
    }
}

/* Mobile — single column, hamburger menu */
@media (max-width: 768px) {
    .header {
        height: 52px;
    }

    .header-inner {
        padding: 0 1rem;
    }

    .header-tag {
        display: none;
    }

    .header-right {
        gap: 0.75rem;
    }

    .header-right a {
        font-size: 0.78rem;
    }

    .mobile-menu-btn {
        display: block;
    }

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

    .sidebar {
        position: fixed;
        top: 52px;
        left: 0;
        right: 0;
        bottom: 0;
        width: 100%;
        height: calc(100vh - 52px);
        background: var(--bg);
        z-index: 50;
        padding: 1.5rem 1.25rem;
        border-right: none;
        transform: translateX(-100%);
        transition: transform 0.25s ease;
    }

    .sidebar.open {
        transform: translateX(0);
    }

    .content {
        padding: 2rem 1.25rem 4rem;
    }

    .content h1 {
        font-size: 2rem;
    }

    .content h2 {
        font-size: 1.5rem;
        margin: 2.5rem 0 0.75rem;
    }

    .content h3 {
        font-size: 1.1rem;
    }

    .content p {
        font-size: 0.95rem;
    }

    .content p:first-of-type {
        font-size: 1rem;
    }

    .content table {
        font-size: 0.78rem;
        display: block;
        overflow-x: auto;
    }

    .content pre {
        padding: 1rem;
        font-size: 0.78rem;
    }

    .chapter-nav {
        grid-template-columns: 1fr;
    }

    /* Landing mobile */
    .hero {
        padding: 3rem 1.25rem 2.5rem;
    }

    .hero h1 {
        font-size: 2.4rem;
    }

    .hero-subtitle {
        font-size: 1rem;
    }

    .hero-description {
        font-size: 0.9rem;
    }

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

    .btn {
        justify-content: center;
    }

    .hero-stats {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.25rem;
    }

    .hero-stat-value {
        font-size: 1.75rem;
    }

    .landing-toc {
        padding: 0 1.25rem;
        margin: 2.5rem auto;
    }

    .landing-toc-title {
        font-size: 1.6rem;
        margin-bottom: 2rem;
    }

    .landing-chapter {
        padding: 0.85rem 1rem;
        gap: 0.75rem;
    }

    .landing-chapter-title {
        font-size: 0.92rem;
    }

    .landing-chapter-desc {
        font-size: 0.75rem;
    }

    .landing-chapter-time {
        display: none;
    }
}