/* ============================================================
   Tuning Labs — Interactive User Manual Stylesheet
   Version: 2026-05-09
   ============================================================ */

:root {
  --bg: #05070d;
  --surface: #0c1220;
  --surface2: #111a2b;
  --surface3: #172035;
  --border: rgba(255,255,255,.08);
  --border2: rgba(255,255,255,.12);
  --text: #e8eeff;
  --muted: #8fa0c0;
  --accent: #16c0ff;
  --accent2: #ff1236;
  --green: #34d399;
  --amber: #fbbf24;
  --purple: #a78bfa;
  --sidebar-w: 280px;
  --topbar-h: 56px;
  --radius: 10px;
  --shadow: 0 8px 32px rgba(0,0,0,.45);
}

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

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, Arial, sans-serif;
  font-size: 15px;
  line-height: 1.7;
  min-height: 100vh;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; border-radius: var(--radius); }

/* ── Top bar ── */
.m-topbar {
  position: fixed;
  top: 0; left: 0; right: 0;
  height: var(--topbar-h);
  background: rgba(5,7,13,.95);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 0 20px;
  z-index: 200;
}

.m-topbar .logo {
  display: flex; align-items: center; gap: 10px;
  font-weight: 700; font-size: 1rem; color: var(--text);
  text-decoration: none; white-space: nowrap;
}
.m-topbar .logo img { width: 28px; height: 28px; border-radius: 6px; }
.m-topbar .logo span { color: var(--accent); }

.m-topbar .chapter-title {
  font-size: .82rem;
  color: var(--muted);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  flex: 1;
}
.m-topbar .chapter-title strong { color: var(--text); }

.m-search-wrap {
  position: relative;
  flex: 0 0 260px;
}
.m-search {
  width: 100%;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  color: var(--text);
  padding: 7px 12px 7px 34px;
  font-size: .82rem;
}
.m-search::placeholder { color: var(--muted); }
.m-search:focus { outline: none; border-color: var(--accent); }
.m-search-icon {
  position: absolute; left: 10px; top: 50%; transform: translateY(-50%);
  color: var(--muted); font-size: .85rem; pointer-events: none;
}
.m-search-results {
  display: none;
  position: absolute;
  top: calc(100% + 6px); left: 0; right: 0;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  max-height: 320px;
  overflow-y: auto;
  z-index: 300;
}
.m-search-results.show { display: block; }
.m-search-result {
  padding: 9px 14px;
  cursor: pointer;
  border-bottom: 1px solid var(--border);
  font-size: .82rem;
}
.m-search-result:last-child { border-bottom: none; }
.m-search-result:hover { background: var(--surface3); }
.m-search-result .sr-chapter { font-size: .72rem; color: var(--muted); margin-bottom: 2px; }
.m-search-result .sr-title { color: var(--text); }
.m-search-result mark { background: rgba(22,192,255,.25); color: var(--accent); border-radius: 2px; padding: 0 2px; }

.m-topbar .nav-toggle {
  display: none;
  background: none; border: none; color: var(--text);
  font-size: 1.3rem; cursor: pointer; padding: 4px 8px;
}

.m-topbar .topbar-links { display: flex; align-items: center; gap: 10px; }
.m-topbar .topbar-links a {
  font-size: .78rem; color: var(--muted);
  padding: 5px 10px; border-radius: 6px;
  transition: background .15s, color .15s;
}
.m-topbar .topbar-links a:hover { background: var(--surface2); color: var(--text); text-decoration: none; }
.m-topbar .topbar-links .btn-app {
  background: var(--accent2);
  color: #fff;
  font-weight: 600;
}
.m-topbar .topbar-links .btn-app:hover { background: #e00f2f; }

/* ── Layout ── */
.m-layout {
  display: flex;
  align-items: flex-start;
  margin-top: var(--topbar-h);
  margin-left: var(--sidebar-w);
  min-height: calc(100vh - var(--topbar-h));
}

/* ── Sidebar ── */
.m-sidebar {
  position: fixed;
  top: var(--topbar-h);
  left: 0;
  width: var(--sidebar-w);
  height: calc(100vh - var(--topbar-h));
  overflow-y: auto;
  background: var(--surface);
  border-right: 1px solid var(--border);
  padding: 16px 0 40px;
  z-index: 100;
  scrollbar-width: thin;
  scrollbar-color: var(--border2) transparent;
}

.m-sidebar::-webkit-scrollbar { width: 4px; }
.m-sidebar::-webkit-scrollbar-track { background: transparent; }
.m-sidebar::-webkit-scrollbar-thumb { background: var(--border2); border-radius: 4px; }

.m-nav-section {
  padding: 0 12px;
  margin-bottom: 8px;
}
.m-nav-label {
  font-size: .68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .08em;
  color: var(--muted);
  padding: 10px 8px 4px;
}
.m-nav-item {
  display: flex;
  align-items: center;
  gap: 9px;
  padding: 8px 10px;
  border-radius: 8px;
  color: var(--muted);
  font-size: .84rem;
  cursor: pointer;
  transition: background .12s, color .12s;
  text-decoration: none;
}
.m-nav-item:hover { background: var(--surface2); color: var(--text); text-decoration: none; }
.m-nav-item.active { background: rgba(22,192,255,.1); color: var(--accent); }
.m-nav-item .nav-icon { font-size: .95rem; width: 18px; text-align: center; flex-shrink: 0; }
.m-nav-item .nav-num {
  font-size: .68rem;
  background: var(--surface3);
  color: var(--muted);
  border-radius: 4px;
  padding: 1px 5px;
  margin-left: auto;
}
.m-nav-item.active .nav-num { background: rgba(22,192,255,.15); color: var(--accent); }

.m-nav-divider { border: none; border-top: 1px solid var(--border); margin: 8px 12px; }

.m-progress-bar {
  margin: 0 12px 16px;
  height: 3px;
  background: var(--surface3);
  border-radius: 3px;
  overflow: hidden;
}
.m-progress-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--accent), var(--accent2));
  border-radius: 3px;
  transition: width .4s ease;
}
.m-progress-label {
  font-size: .7rem; color: var(--muted);
  padding: 4px 12px 8px;
}

/* ── Main content ── */
.m-content {
  flex: 1;
  min-width: 0;
  padding: 40px 52px 80px;
  max-width: 860px;
}

/* ── Chapter header ── */
.ch-header {
  margin-bottom: 36px;
  padding-bottom: 24px;
  border-bottom: 1px solid var(--border);
}
.ch-badge {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(22,192,255,.1); border: 1px solid rgba(22,192,255,.2);
  color: var(--accent); font-size: .72rem; font-weight: 700;
  padding: 3px 10px; border-radius: 20px; margin-bottom: 12px;
  text-transform: uppercase; letter-spacing: .06em;
}
.ch-title {
  font-size: 2rem; font-weight: 800;
  color: #fff; line-height: 1.2;
  margin-bottom: 10px;
}
.ch-subtitle {
  font-size: 1rem; color: var(--muted);
  max-width: 620px;
}
.ch-meta {
  display: flex; gap: 20px; flex-wrap: wrap;
  margin-top: 16px;
}
.ch-meta-item {
  display: flex; align-items: center; gap: 6px;
  font-size: .78rem; color: var(--muted);
}
.ch-meta-item .dot { width: 6px; height: 6px; border-radius: 50%; background: var(--accent); }

/* ── Section headings ── */
.m-content h2 {
  font-size: 1.35rem; font-weight: 700;
  color: #fff;
  margin: 40px 0 14px;
  padding-top: 8px;
  scroll-margin-top: calc(var(--topbar-h) + 20px);
}
.m-content h3 {
  font-size: 1.05rem; font-weight: 600;
  color: var(--accent);
  margin: 28px 0 10px;
  scroll-margin-top: calc(var(--topbar-h) + 20px);
}
.m-content h4 {
  font-size: .92rem; font-weight: 600;
  color: var(--amber);
  margin: 20px 0 8px;
}
.m-content p { margin-bottom: 14px; color: rgba(232,238,255,.85); }
.m-content ul, .m-content ol { margin: 0 0 14px 22px; }
.m-content li { margin-bottom: 6px; color: rgba(232,238,255,.8); }
.m-content strong { color: var(--text); }
.m-content code {
  background: rgba(22,192,255,.1);
  color: var(--accent);
  padding: 1px 6px; border-radius: 4px;
  font-family: 'Courier New', monospace;
  font-size: .88em;
}

/* ── Screenshot blocks ── */
.screenshot-block {
  margin: 24px 0;
  border-radius: var(--radius);
  overflow: hidden;
  border: 1px solid var(--border2);
  box-shadow: var(--shadow);
}
.screenshot-block img {
  width: 100%;
  display: block;
  border-radius: 0;
}
.screenshot-caption {
  background: var(--surface2);
  padding: 8px 14px;
  font-size: .78rem; color: var(--muted);
  border-top: 1px solid var(--border);
  display: flex; align-items: center; gap: 6px;
}
.screenshot-caption .cam { color: var(--accent); }

.screenshot-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin: 24px 0;
}
.screenshot-grid .screenshot-block { margin: 0; }

/* ── Callout boxes ── */
.callout {
  border-radius: var(--radius);
  padding: 14px 18px;
  margin: 20px 0;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}
.callout .callout-icon { font-size: 1.1rem; flex-shrink: 0; margin-top: 1px; }
.callout .callout-body { flex: 1; }
.callout .callout-title { font-weight: 700; font-size: .88rem; margin-bottom: 4px; }
.callout .callout-text { font-size: .84rem; color: rgba(232,238,255,.8); margin: 0; }

.callout.info { background: rgba(22,192,255,.08); border: 1px solid rgba(22,192,255,.2); }
.callout.info .callout-icon, .callout.info .callout-title { color: var(--accent); }

.callout.warning { background: rgba(251,191,36,.08); border: 1px solid rgba(251,191,36,.2); }
.callout.warning .callout-icon, .callout.warning .callout-title { color: var(--amber); }

.callout.danger { background: rgba(255,18,54,.08); border: 1px solid rgba(255,18,54,.2); }
.callout.danger .callout-icon, .callout.danger .callout-title { color: var(--accent2); }

.callout.success { background: rgba(52,211,153,.08); border: 1px solid rgba(52,211,153,.2); }
.callout.success .callout-icon, .callout.success .callout-title { color: var(--green); }

.callout.tip { background: rgba(167,139,250,.08); border: 1px solid rgba(167,139,250,.2); }
.callout.tip .callout-icon, .callout.tip .callout-title { color: var(--purple); }

/* ── Step blocks ── */
.steps {
  counter-reset: step-counter;
  margin: 24px 0;
}
.step {
  display: flex; gap: 16px;
  margin-bottom: 20px;
  counter-increment: step-counter;
}
.step-num {
  flex-shrink: 0;
  width: 32px; height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  display: flex; align-items: center; justify-content: center;
  font-size: .82rem; font-weight: 800; color: #000;
  margin-top: 2px;
}
.step-body { flex: 1; }
.step-body h4 { margin: 0 0 6px; color: var(--text); font-size: .95rem; }
.step-body p { margin: 0; font-size: .88rem; color: rgba(232,238,255,.8); }

/* ── Dependency tree ── */
.dep-tree {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  padding: 20px 24px;
  margin: 24px 0;
}
.dep-tree h4 { margin: 0 0 16px; color: var(--amber); font-size: .9rem; }
.dep-node {
  display: flex; align-items: center; gap: 10px;
  padding: 8px 12px;
  border-radius: 8px;
  margin-bottom: 6px;
  font-size: .85rem;
}
.dep-node.required { background: rgba(255,18,54,.08); border: 1px solid rgba(255,18,54,.2); color: var(--text); }
.dep-node.optional { background: rgba(251,191,36,.06); border: 1px solid rgba(251,191,36,.15); color: var(--text); }
.dep-node.done { background: rgba(52,211,153,.08); border: 1px solid rgba(52,211,153,.2); color: var(--text); }
.dep-node .dep-icon { font-size: 1rem; flex-shrink: 0; }
.dep-node .dep-label { flex: 1; font-weight: 600; }
.dep-node .dep-badge {
  font-size: .68rem; font-weight: 700; text-transform: uppercase; padding: 2px 7px; border-radius: 4px;
}
.dep-node.required .dep-badge { background: rgba(255,18,54,.2); color: var(--accent2); }
.dep-node.optional .dep-badge { background: rgba(251,191,36,.15); color: var(--amber); }
.dep-node.done .dep-badge { background: rgba(52,211,153,.15); color: var(--green); }
.dep-arrow {
  color: var(--muted); font-size: .75rem; margin-left: 24px; margin-bottom: 6px;
}

/* ── Feature table ── */
.feature-table {
  width: 100%;
  border-collapse: collapse;
  margin: 20px 0;
  font-size: .84rem;
}
.feature-table th {
  text-align: left;
  padding: 8px 12px;
  color: var(--muted);
  font-size: .72rem;
  text-transform: uppercase;
  letter-spacing: .06em;
  border-bottom: 1px solid var(--border2);
}
.feature-table td {
  padding: 10px 12px;
  border-bottom: 1px solid var(--border);
  color: rgba(232,238,255,.8);
  vertical-align: top;
}
.feature-table tr:hover td { background: var(--surface2); }
.feature-table .check { color: var(--green); }
.feature-table .cross { color: var(--muted); }

/* ── Tier badges ── */
.tier-ae { background: rgba(22,192,255,.12); border: 1px solid rgba(22,192,255,.25); color: var(--accent); font-size: .7rem; font-weight: 700; padding: 2px 8px; border-radius: 4px; white-space: nowrap; }
.tier-ss { background: rgba(167,139,250,.12); border: 1px solid rgba(167,139,250,.25); color: var(--purple); font-size: .7rem; font-weight: 700; padding: 2px 8px; border-radius: 4px; white-space: nowrap; }
.tier-sl { background: rgba(251,191,36,.12); border: 1px solid rgba(251,191,36,.25); color: var(--amber); font-size: .7rem; font-weight: 700; padding: 2px 8px; border-radius: 4px; white-space: nowrap; }

/* ── Page navigation (prev/next) ── */
.ch-pagination {
  display: flex; justify-content: space-between; align-items: center;
  margin-top: 60px;
  padding-top: 24px;
  border-top: 1px solid var(--border);
  gap: 16px;
}
.ch-page-btn {
  display: flex; align-items: center; gap: 10px;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: var(--radius);
  padding: 12px 18px;
  color: var(--text);
  text-decoration: none;
  font-size: .84rem;
  transition: background .15s, border-color .15s;
  max-width: 45%;
}
.ch-page-btn:hover { background: var(--surface3); border-color: var(--accent); text-decoration: none; }
.ch-page-btn .pdir { font-size: .72rem; color: var(--muted); display: block; margin-bottom: 2px; }
.ch-page-btn .ptitle { font-weight: 600; color: var(--text); }
.ch-page-btn.next { margin-left: auto; text-align: right; flex-direction: row-reverse; }

/* ── On-page TOC ── */
/* Always hide the inline .on-page-toc inside .m-content — it lives in .m-rightbar */
.m-content .on-page-toc { display: none !important; }

.on-page-toc {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 12px 14px;
  font-size: .75rem;
  display: none;
}
.on-page-toc h5 { font-size: .68rem; text-transform: uppercase; letter-spacing: .08em; color: var(--muted); margin-bottom: 8px; }
.on-page-toc a { display: block; color: var(--muted); padding: 3px 0; transition: color .12s; }
.on-page-toc a:hover, .on-page-toc a.active { color: var(--accent); text-decoration: none; }

@media (min-width: 1400px) {
  .m-content { max-width: 820px; }
}

/* ── AI Chat Widget ── */
#ai-chat-btn {
  position: fixed;
  bottom: 28px; right: 28px;
  width: 54px; height: 54px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  border: none;
  color: #000;
  font-size: 1.3rem;
  cursor: pointer;
  box-shadow: 0 4px 20px rgba(22,192,255,.4);
  display: flex; align-items: center; justify-content: center;
  z-index: 400;
  transition: transform .2s, box-shadow .2s;
}
#ai-chat-btn:hover { transform: scale(1.08); box-shadow: 0 6px 28px rgba(22,192,255,.5); }
#ai-chat-btn .ai-notif {
  position: absolute; top: -2px; right: -2px;
  width: 14px; height: 14px;
  background: var(--accent2);
  border-radius: 50%;
  border: 2px solid var(--bg);
  display: none;
}

#ai-chat-panel {
  position: fixed;
  bottom: 96px; right: 28px;
  width: 380px;
  max-height: 520px;
  background: var(--surface);
  border: 1px solid var(--border2);
  border-radius: 14px;
  box-shadow: var(--shadow);
  display: flex; flex-direction: column;
  z-index: 400;
  overflow: hidden;
  transform: scale(.95) translateY(10px);
  opacity: 0;
  pointer-events: none;
  transition: transform .2s, opacity .2s;
}
#ai-chat-panel.open {
  transform: scale(1) translateY(0);
  opacity: 1;
  pointer-events: all;
}

.ai-panel-head {
  padding: 14px 16px;
  background: var(--surface2);
  border-bottom: 1px solid var(--border);
  display: flex; align-items: center; gap: 10px;
}
.ai-panel-head .ai-avatar {
  width: 32px; height: 32px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  display: flex; align-items: center; justify-content: center;
  font-size: .85rem; color: #000; font-weight: 800;
  flex-shrink: 0;
}
.ai-panel-head .ai-info { flex: 1; }
.ai-panel-head .ai-name { font-size: .88rem; font-weight: 700; }
.ai-panel-head .ai-status { font-size: .72rem; color: var(--green); }
.ai-panel-close {
  background: none; border: none; color: var(--muted); cursor: pointer; font-size: 1rem; padding: 4px;
}
.ai-panel-close:hover { color: var(--text); }

.ai-messages {
  flex: 1; overflow-y: auto;
  padding: 14px;
  display: flex; flex-direction: column; gap: 10px;
  scrollbar-width: thin;
  scrollbar-color: var(--border2) transparent;
}

.ai-msg {
  max-width: 88%;
  padding: 9px 13px;
  border-radius: 10px;
  font-size: .83rem;
  line-height: 1.55;
}
.ai-msg.bot {
  background: var(--surface2);
  border: 1px solid var(--border);
  align-self: flex-start;
  color: var(--text);
}
.ai-msg.user {
  background: rgba(22,192,255,.15);
  border: 1px solid rgba(22,192,255,.2);
  align-self: flex-end;
  color: var(--text);
}
.ai-msg.typing { color: var(--muted); font-style: italic; }

.ai-suggestions {
  padding: 0 14px 10px;
  display: flex; flex-wrap: wrap; gap: 6px;
}
.ai-suggestion {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 20px;
  padding: 4px 12px;
  font-size: .75rem; color: var(--muted);
  cursor: pointer;
  transition: border-color .12s, color .12s;
}
.ai-suggestion:hover { border-color: var(--accent); color: var(--accent); }

.ai-input-row {
  padding: 10px 12px;
  border-top: 1px solid var(--border);
  display: flex; gap: 8px;
}
.ai-input {
  flex: 1;
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 8px;
  color: var(--text);
  padding: 8px 12px;
  font-size: .82rem;
  resize: none;
  max-height: 80px;
}
.ai-input:focus { outline: none; border-color: var(--accent); }
.ai-send {
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  border: none; border-radius: 8px;
  width: 36px; height: 36px;
  display: flex; align-items: center; justify-content: center;
  cursor: pointer; color: #000; font-size: .9rem;
  flex-shrink: 0;
  align-self: flex-end;
}
.ai-send:hover { opacity: .85; }

/* ── Index / Home page specific ── */
.manual-hero {
  text-align: center;
  padding: 60px 20px 48px;
}
.manual-hero .hero-badge {
  display: inline-flex; align-items: center; gap: 6px;
  background: rgba(22,192,255,.1); border: 1px solid rgba(22,192,255,.2);
  color: var(--accent); font-size: .78rem; font-weight: 700;
  padding: 5px 14px; border-radius: 20px; margin-bottom: 20px;
}
.manual-hero h1 {
  font-size: 2.8rem; font-weight: 900;
  color: #fff; line-height: 1.15; margin-bottom: 16px;
}
.manual-hero h1 span { color: var(--accent); }
.manual-hero p { font-size: 1.05rem; color: var(--muted); max-width: 560px; margin: 0 auto 28px; }
.manual-hero .hero-actions { display: flex; gap: 12px; justify-content: center; flex-wrap: wrap; }
.btn-primary {
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  color: #000; font-weight: 700;
  padding: 11px 24px; border-radius: 8px;
  font-size: .88rem; text-decoration: none;
  transition: opacity .15s;
}
.btn-primary:hover { opacity: .85; text-decoration: none; }
.btn-secondary {
  background: var(--surface2);
  border: 1px solid var(--border2);
  color: var(--text); font-weight: 600;
  padding: 11px 24px; border-radius: 8px;
  font-size: .88rem; text-decoration: none;
  transition: border-color .15s;
}
.btn-secondary:hover { border-color: var(--accent); text-decoration: none; }

.chapter-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 16px;
  padding: 0 32px 60px;
  max-width: 1100px;
  margin: 0 auto;
}
.chapter-card {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 20px;
  text-decoration: none;
  color: var(--text);
  transition: border-color .15s, transform .15s;
  display: block;
}
.chapter-card:hover { border-color: var(--accent); transform: translateY(-2px); text-decoration: none; }
.chapter-card .cc-icon {
  font-size: 1.6rem; margin-bottom: 12px;
  display: block;
}
.chapter-card .cc-num {
  font-size: .7rem; font-weight: 700; text-transform: uppercase;
  color: var(--muted); margin-bottom: 4px;
}
.chapter-card .cc-title {
  font-size: 1.05rem; font-weight: 700;
  color: var(--text); margin-bottom: 8px;
}
.chapter-card .cc-desc {
  font-size: .8rem; color: var(--muted); line-height: 1.5;
}

/* ═══════════════════════════════════════════════════════════
   CHAPTER PAGE COMPONENTS — added 2026-05-09
   ═══════════════════════════════════════════════════════════ */

/* ── Chapter hero (used in each chapter page) ── */
.chapter-hero {
  margin-bottom: 36px;
  padding-bottom: 28px;
  border-bottom: 1px solid var(--border);
}
.chapter-hero .ch-meta {
  font-size: .72rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .06em; color: var(--accent); margin-bottom: 10px;
}
.chapter-hero h1 {
  font-size: 2.2rem; font-weight: 900; color: #fff;
  line-height: 1.15; margin-bottom: 12px;
}
.chapter-hero .ch-lead {
  font-size: 1rem; color: var(--muted);
  max-width: 640px; margin-bottom: 18px; line-height: 1.65;
}
.ch-badges { display: flex; flex-wrap: wrap; gap: 8px; }
.badge {
  display: inline-flex; align-items: center;
  font-size: .7rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: .05em; padding: 3px 10px; border-radius: 20px;
}
.badge-green  { background: rgba(52,211,153,.12);  border: 1px solid rgba(52,211,153,.25);  color: var(--green); }
.badge-blue   { background: rgba(22,192,255,.1);   border: 1px solid rgba(22,192,255,.2);   color: var(--accent); }
.badge-red    { background: rgba(255,18,54,.1);    border: 1px solid rgba(255,18,54,.25);   color: var(--accent2); }
.badge-purple { background: rgba(167,139,250,.1);  border: 1px solid rgba(167,139,250,.25); color: var(--purple); }
.badge-orange { background: rgba(251,146,60,.1);   border: 1px solid rgba(251,146,60,.25);  color: #fb923c; }

/* ── Callout aliases (short class names used in chapters) ── */
.callout { padding: 14px 16px; border-radius: 9px; margin: 20px 0; font-size: .86rem; line-height: 1.6; }
.callout strong { display: block; margin-bottom: 4px; }
.callout-tip   { background: rgba(167,139,250,.08); border: 1px solid rgba(167,139,250,.2); color: rgba(232,238,255,.85); }
.callout-tip strong { color: var(--purple); }
.callout-info  { background: rgba(22,192,255,.08);  border: 1px solid rgba(22,192,255,.2);  color: rgba(232,238,255,.85); }
.callout-info strong { color: var(--accent); }
.callout-warn  { background: rgba(251,191,36,.08);  border: 1px solid rgba(251,191,36,.2);  color: rgba(232,238,255,.85); }
.callout-warn strong { color: var(--amber); }

/* ── Numbered steps (chapter-page variant) ── */
.steps-numbered { margin: 24px 0; }
.step-n {
  display: flex; gap: 16px; margin-bottom: 18px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 10px; padding: 14px 16px;
}
.step-n .step-num {
  flex-shrink: 0; width: 30px; height: 30px; border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), #0e7aaa);
  display: flex; align-items: center; justify-content: center;
  font-size: .8rem; font-weight: 800; color: #000; margin-top: 2px;
}
.step-n .step-body { flex: 1; font-size: .875rem; color: rgba(232,238,255,.85); }
.step-n .step-body strong { color: var(--text); display: block; margin-bottom: 4px; }

/* ── Letter-step blocks (A/B style) ── */
.step-block { margin: 24px 0; }
.step-block .step {
  display: flex; gap: 16px; margin-bottom: 14px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 10px; padding: 14px 16px;
}
.step-block .step-body { flex: 1; font-size: .875rem; color: rgba(232,238,255,.85); }
.step-block .step-body strong { color: var(--text); display: block; margin-bottom: 4px; }

/* ── Two-column layout ── */
.two-col {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
  margin: 20px 0;
}
.two-col-item {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 18px;
}
.two-col-item h4 { font-size: .88rem; font-weight: 700; color: var(--amber); margin-bottom: 10px; }
@media (max-width: 700px) { .two-col { grid-template-columns: 1fr; } }

/* ── Dependency tree (chapter-page style) ── */
.dep-root {
  background: rgba(22,192,255,.08); border: 1px solid rgba(22,192,255,.2);
  border-radius: 10px; padding: 12px 16px;
  display: flex; align-items: center; gap: 12px; margin-bottom: 16px;
}
.dep-root .dep-label { font-weight: 800; color: var(--accent); font-size: .95rem; }
.dep-root .dep-note { font-size: .75rem; color: var(--muted); margin-left: auto; }
.dep-root .dep-icon { font-size: 1.3rem; }
.dep-children { padding-left: 28px; border-left: 2px solid var(--border2); margin-left: 20px; }
.dep-branch { margin-bottom: 12px; }
.dep-node {
  display: flex; align-items: center; gap: 10px;
  background: var(--surface2); border: 1px solid var(--border);
  border-radius: 9px; padding: 10px 14px; margin-bottom: 6px;
  font-size: .85rem;
}
.dep-node.dep-req { border-color: rgba(255,18,54,.25); background: rgba(255,18,54,.05); }
.dep-node.dep-end { border-color: rgba(52,211,153,.25); background: rgba(52,211,153,.05); }
.dep-node .dep-icon { font-size: 1rem; flex-shrink: 0; }
.dep-node .dep-label { flex: 1; font-weight: 600; color: var(--text); }
.dep-node .dep-note { font-size: .72rem; color: var(--muted); }
.dep-detail { padding-left: 20px; margin-bottom: 8px; }
.dep-detail ul { margin: 6px 0 0 16px; }
.dep-detail li { font-size: .8rem; color: var(--muted); margin-bottom: 3px; }

/* ── Feature table wrapper ── */
.feature-table-wrap { overflow-x: auto; margin: 20px 0; }
.feature-table-wrap .feature-table { margin: 0; }

/* ── Tier badge aliases ── */
.tier-badge { font-size: .72rem; font-weight: 700; padding: 2px 8px; border-radius: 4px; white-space: nowrap; display: inline-block; }
.tier-ae    { background: rgba(22,192,255,.12);  border: 1px solid rgba(22,192,255,.25);  color: var(--accent); }
.tier-small { background: rgba(167,139,250,.12); border: 1px solid rgba(167,139,250,.25); color: var(--purple); }
.tier-large { background: rgba(251,191,36,.12);  border: 1px solid rgba(251,191,36,.25);  color: var(--amber); }

/* ── Screenshot caption ── */
.caption {
  font-size: .78rem; color: var(--muted);
  text-align: center; padding: 10px 16px;
  background: var(--surface2);
  border-top: 1px solid var(--border);
  margin: 0;
}

/* ── Next chapter box ── */
.next-chapter-box {
  display: flex; align-items: center; justify-content: space-between;
  gap: 20px; flex-wrap: wrap;
  background: linear-gradient(135deg, rgba(22,192,255,.07), rgba(22,192,255,.03));
  border: 1px solid rgba(22,192,255,.2);
  border-radius: 12px; padding: 24px 28px;
  margin: 48px 0 32px;
}
.ncb-text strong { display: block; font-size: 1rem; font-weight: 700; color: #fff; margin-bottom: 4px; }
.ncb-text p { font-size: .84rem; color: var(--muted); margin: 0; }

/* ── Pagination (prev/next) ── */
.m-pagination {
  display: flex; justify-content: space-between; align-items: center;
  padding-top: 24px; margin-top: 16px;
  border-top: 1px solid var(--border);
}
.pag-prev, .pag-next {
  background: var(--surface2); border: 1px solid var(--border2);
  border-radius: 9px; padding: 10px 18px;
  font-size: .84rem; font-weight: 600; color: var(--text);
  text-decoration: none; transition: border-color .15s;
}
.pag-prev:hover, .pag-next:hover { border-color: var(--accent); text-decoration: none; }

/* ── AI Mode cards (Chapter 10) ── */
.ai-mode-card {
  background: var(--surface2);
  border: 1px solid var(--border2);
  border-radius: 12px;
  margin-bottom: 20px;
  overflow: hidden;
}
.ai-mode-header {
  display: flex; align-items: center; gap: 14px;
  padding: 14px 20px;
  background: var(--surface3);
  border-bottom: 1px solid var(--border);
}
.ai-mode-num {
  font-size: .72rem; font-weight: 800; font-family: monospace;
  color: var(--accent); letter-spacing: .08em;
}
.ai-mode-name { font-size: .98rem; font-weight: 700; color: var(--text); }
.ai-mode-body { padding: 16px 20px; font-size: .86rem; color: rgba(232,238,255,.85); }
.ai-mode-body p { margin-bottom: 8px; }
.ai-mode-body strong { color: var(--text); }

/* ── Right bar (TOC column) ── */
.m-rightbar {
  display: none;
  width: 240px;
  flex-shrink: 0;
  padding: 32px 20px 40px 0;
}
@media (min-width: 1400px) {
  .m-rightbar { display: block; }
  .m-rightbar .on-page-toc {
    display: block;
    position: sticky;
    top: calc(var(--topbar-h) + 20px);
    max-height: calc(100vh - var(--topbar-h) - 40px);
    overflow-y: auto;
  }
}

/* ── m-topnav (top nav links) ── */
.m-topnav { display: flex; align-items: center; gap: 6px; margin-left: auto; }
.m-topnav a {
  color: var(--muted); font-size: .82rem; text-decoration: none;
  padding: 5px 10px; border-radius: 6px; transition: background .15s;
  white-space: nowrap;
}
.m-topnav a:hover { background: var(--surface2); color: var(--text); text-decoration: none; }
.m-topnav .btn-app {
  background: var(--accent2); color: #fff !important;
  font-weight: 700; border-radius: 7px;
}
.m-topnav .btn-app:hover { background: #d00f2a !important; }

.chapter-card.featured { border-color: rgba(22,192,255,.3); background: rgba(22,192,255,.04); }
.chapter-card.featured .cc-title { color: var(--accent); }

/* ── Responsive ── */
@media (max-width: 900px) {
  .m-topbar .nav-toggle { display: block; }
  .m-topbar .chapter-title { display: none; }
  .m-search-wrap { flex: 0 0 180px; }

  .m-sidebar {
    transform: translateX(-100%);
    transition: transform .25s;
  }
  .m-sidebar.open { transform: translateX(0); }

  .m-layout { grid-template-columns: 1fr; }
  .m-content { margin-left: 0; padding: 24px 20px 60px; }

  .screenshot-grid { grid-template-columns: 1fr; }
  .ch-title { font-size: 1.5rem; }
  .manual-hero h1 { font-size: 1.9rem; }

  #ai-chat-panel { width: calc(100vw - 32px); right: 16px; bottom: 80px; }

  .chapter-grid { padding: 0 16px 40px; }
}

@media (max-width: 600px) {
  .m-search-wrap { display: none; }
  .m-topbar .topbar-links .btn-app { display: none; }
}