:root {
  --bg: #0a0a0a;
  --bg-elev: #121212;
  --bg-hover: #1a1a1a;
  --border: #1f1f1f;
  --text: #e8e8e8;
  --text-dim: #8a8a8a;
  --text-mute: #5a5a5a;
  --accent: #A3E635;
  --accent-dim: #6b9423;
  --radius: 6px;
  --sidebar-w: 280px;
  --toc-w: 220px;
  --content-max: 720px;
}

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

html { scroll-behavior: smooth; scroll-padding-top: 24px; }

body {
  font-family: 'Inter', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

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

/* ===== Layout ===== */
.layout {
  display: grid;
  grid-template-columns: var(--sidebar-w) 1fr var(--toc-w);
  max-width: 1400px;
  margin: 0 auto;
  min-height: 100vh;
}

/* ===== Sidebar ===== */
.sidebar {
  border-right: 1px solid var(--border);
  padding: 28px 24px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
}

.sidebar-brand {
  display: block;
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--border);
  text-decoration: none;
}

.sidebar-brand:hover { text-decoration: none; }

.sidebar-brand .brand-row {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 12px;
}

.sidebar-brand .claude-mark {
  width: 26px;
  height: 26px;
  display: block;
  flex-shrink: 0;
}

.sidebar-brand .brand-title {
  font-family: 'Outfit', sans-serif;
  font-size: 19px;
  font-weight: 600;
  color: var(--text);
  letter-spacing: -0.01em;
  line-height: 1;
}

.sidebar-brand .brand-by {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-left: 36px;
}

.sidebar-brand .by-label {
  font-size: 11px;
  color: var(--text-mute);
  letter-spacing: 0.02em;
}

.sidebar-brand .sasoy-mark {
  height: 18px;
  width: auto;
  display: block;
}

.nav-section {
  margin-bottom: 22px;
}

.nav-section-title {
  font-family: 'Outfit', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 8px;
  padding: 0 8px;
}

.nav-list {
  list-style: none;
}

.nav-list a {
  display: block;
  padding: 6px 8px;
  color: var(--text-dim);
  font-size: 14px;
  border-radius: var(--radius);
  text-decoration: none;
  transition: all 0.15s;
}

.nav-list a:hover {
  background: var(--bg-hover);
  color: var(--text);
}

.nav-list a.active {
  background: var(--bg-hover);
  color: var(--accent);
  font-weight: 500;
}

/* ===== Main content ===== */
.main {
  padding: 64px 56px 120px;
  max-width: calc(var(--content-max) + 112px);
}

.chapter-meta {
  font-family: 'Outfit', sans-serif;
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 16px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.chapter-meta::before {
  content: '';
  width: 28px;
  height: 1px;
  background: var(--accent);
  flex-shrink: 0;
}

/* Chapter brand logos (e.g., LeonardoAI × Claude) */
.chapter-logos {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 24px;
}
.chapter-logos img {
  width: 36px;
  height: 36px;
  border-radius: 8px;
  object-fit: contain;
}
.chapter-logos .logo-x {
  font-size: 18px;
  color: var(--text-mute);
  font-weight: 300;
}

h1 {
  font-family: 'Outfit', sans-serif;
  font-size: 44px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--text);
  margin-bottom: 20px;
}

h2 {
  font-family: 'Outfit', sans-serif;
  font-size: 26px;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text);
  margin: 48px 0 16px;
  scroll-margin-top: 24px;
}

h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 19px;
  font-weight: 600;
  color: var(--text);
  margin: 32px 0 12px;
}

.lede {
  font-size: 19px;
  color: var(--text-dim);
  line-height: 1.6;
  margin-bottom: 40px;
  max-width: var(--content-max);
}

p, ul, ol {
  max-width: var(--content-max);
  margin-bottom: 18px;
  color: var(--text);
}

ul, ol { padding-left: 22px; }
li { margin-bottom: 6px; }

strong { color: var(--text); font-weight: 600; }
em { color: var(--text-dim); }

code {
  font-family: 'SF Mono', Menlo, monospace;
  font-size: 13px;
  background: var(--bg-elev);
  padding: 2px 6px;
  border-radius: 4px;
  color: var(--accent);
}

pre {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 16px 18px;
  overflow-x: auto;
  margin-bottom: 18px;
  max-width: var(--content-max);
}

pre code {
  background: transparent;
  padding: 0;
  color: var(--text);
  font-size: 13px;
  line-height: 1.6;
}

blockquote {
  border-left: 3px solid var(--accent);
  padding: 4px 0 4px 20px;
  margin: 24px 0;
  color: var(--text-dim);
  font-style: italic;
  max-width: var(--content-max);
}

.callout {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 24px 0;
  max-width: var(--content-max);
}

.callout-label {
  font-family: 'Outfit', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 6px;
}

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

/* ===== Tables ===== */
.main table {
  width: 100%;
  border-collapse: collapse;
  margin: 16px 0 28px;
  font-size: 14px;
}
.main thead th {
  text-align: left;
  font-family: 'Outfit', sans-serif;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-mute);
  font-weight: 600;
  padding: 12px 16px;
  border-bottom: 1px solid var(--border);
  background: var(--bg-elev);
}
.main tbody td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  vertical-align: top;
  line-height: 1.55;
}
.main tbody tr:last-child td { border-bottom: none; }
.main tbody td code {
  font-size: 13px;
}

/* ===== Rich chapter components (step-cards, prompt-boxes, etc.) ===== */
.meta-pills {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  margin: 16px 0 32px;
}
.meta-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 6px 14px;
  font-size: 13px;
  color: var(--text-dim);
  font-weight: 500;
}
.meta-pill .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.needs-grid {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 12px 0 24px;
}
.need-item {
  display: flex;
  align-items: center;
  gap: 12px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 12px 16px;
  font-size: 14px;
  color: var(--text-dim);
}
.need-item .need-dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.steps {
  display: flex;
  flex-direction: column;
  gap: 16px;
  margin: 16px 0 24px;
}
.step-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px 28px;
}
.step-num {
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 8px;
  font-family: 'Outfit', sans-serif;
}
.step-card h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 18px;
  font-weight: 700;
  color: var(--text);
  margin: 0 0 14px;
  letter-spacing: -0.01em;
}
.step-card p {
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.65;
  margin-bottom: 12px;
}
.step-card p:last-child { margin-bottom: 0; }
.step-card ol, .step-card ul {
  padding-left: 20px;
  margin: 8px 0 12px;
  color: var(--text-dim);
  font-size: 14px;
  line-height: 1.85;
}
.step-card ol li::marker { color: var(--accent); font-weight: 700; }

.prompt-box {
  background: var(--bg);
  border: 1px solid rgba(163, 230, 53, 0.18);
  border-radius: var(--radius);
  padding: 18px 22px;
  margin: 14px 0;
  font-size: 14px;
  color: var(--text-dim);
  line-height: 1.7;
}
.prompt-box .prompt-label {
  font-family: 'Outfit', sans-serif;
  font-size: 11px;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.12em;
  margin-bottom: 10px;
}
.prompt-box pre {
  margin-top: 12px;
}

.tip-callout {
  background: rgba(163, 230, 53, 0.06);
  border: 1px solid rgba(163, 230, 53, 0.18);
  border-radius: var(--radius);
  padding: 12px 16px;
  font-size: 13px;
  color: var(--text);
  font-weight: 500;
  margin-top: 12px;
  display: flex;
  align-items: flex-start;
  gap: 10px;
}
.tip-callout .tip-icon { color: var(--accent); flex-shrink: 0; margin-top: 1px; }

.trouble-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin: 12px 0 24px;
}
.trouble-item {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
}
.trouble-item code {
  font-size: 12px;
  display: inline-block;
  margin-bottom: 6px;
}
.trouble-item p {
  font-size: 13px;
  color: var(--text-dim);
  margin: 0;
  line-height: 1.6;
}

.main code {
  font-family: 'SF Mono', 'Fira Code', monospace;
  font-size: 13px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 2px 6px;
  color: var(--accent);
}

.main pre code {
  background: transparent;
  border: none;
  padding: 0;
  color: inherit;
}

/* ===== Offer block (end-of-chapter CTA) ===== */
.offer-block {
  margin: 56px 0 24px;
  padding: 32px 28px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  position: relative;
  overflow: hidden;
}
.offer-block::before {
  content: "";
  position: absolute;
  top: 0; left: 0;
  width: 4px; height: 100%;
  background: var(--accent);
}
.offer-block .offer-eyebrow {
  display: inline-block;
  font-size: 11px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--accent);
  font-weight: 600;
  margin-bottom: 12px;
}
.offer-block h3 {
  font-family: 'Outfit', sans-serif;
  font-size: 26px;
  font-weight: 600;
  color: var(--text);
  margin: 0 0 12px;
  line-height: 1.25;
}
.offer-block p.lead {
  color: var(--text-dim);
  font-size: 15px;
  line-height: 1.6;
  margin: 0 0 20px;
}
.offer-tier-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 20px 0 24px;
}
@media (max-width: 720px) {
  .offer-tier-grid { grid-template-columns: 1fr; }
}
.offer-tier {
  padding: 16px;
  background: rgba(255,255,255,0.02);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.offer-tier .tier-label {
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 6px;
}
.offer-tier .tier-name {
  font-family: 'Outfit', sans-serif;
  font-size: 16px;
  font-weight: 600;
  color: var(--text);
  margin-bottom: 4px;
}
.offer-tier .tier-detail {
  font-size: 13px;
  color: var(--text-dim);
  line-height: 1.5;
}
.offer-cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}
.offer-cta-primary,
.offer-cta-secondary {
  padding: 12px 22px;
  border-radius: var(--radius);
  font-family: 'Outfit', sans-serif;
  font-weight: 600;
  font-size: 14px;
  text-decoration: none;
  display: inline-block;
  transition: transform 0.15s, background 0.15s, border-color 0.15s;
}
.offer-cta-primary {
  background: var(--accent);
  color: var(--bg);
}
.offer-cta-primary:hover {
  background: var(--accent-dim);
  transform: translateY(-1px);
  text-decoration: none;
}
.offer-cta-secondary {
  background: transparent;
  color: var(--text);
  border: 1px solid var(--border);
}
.offer-cta-secondary:hover {
  border-color: var(--accent);
  text-decoration: none;
}

/* ===== Pager ===== */
.pager {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  margin-top: 80px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
  max-width: var(--content-max);
}

.pager a {
  flex: 1;
  padding: 16px 20px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  text-decoration: none;
  transition: all 0.15s;
}

.pager a:hover {
  border-color: var(--accent);
  transform: translateY(-1px);
}

.pager .dir {
  font-size: 12px;
  color: var(--text-mute);
  margin-bottom: 4px;
}

.pager .title {
  font-family: 'Outfit', sans-serif;
  font-size: 15px;
  color: var(--text);
  font-weight: 500;
}

.pager .next { text-align: right; }

/* ===== TOC (right sidebar) ===== */
.toc {
  padding: 64px 20px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  font-size: 13px;
}

.toc-title {
  font-family: 'Outfit', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-mute);
  margin-bottom: 12px;
}

.toc ul { list-style: none; padding: 0; }
.toc li { margin-bottom: 6px; }
.toc a {
  color: var(--text-dim);
  text-decoration: none;
  display: block;
  padding: 3px 0;
  border-left: 2px solid transparent;
  padding-left: 10px;
  margin-left: -2px;
}
.toc a:hover { color: var(--text); }
.toc a.active { color: var(--accent); border-left-color: var(--accent); }

/* ===== Landing (index) ===== */
.landing {
  padding: 80px 56px 120px;
  max-width: 900px;
}

.landing h1 {
  font-size: 56px;
  margin-bottom: 24px;
}

.landing .tagline {
  font-size: 21px;
  color: var(--text-dim);
  margin-bottom: 48px;
  line-height: 1.5;
  max-width: 640px;
}

.landing .story {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 32px;
  margin-bottom: 56px;
  max-width: 720px;
}

.landing .story p { margin-bottom: 12px; }
.landing .story p:last-child { margin-bottom: 0; }

.landing .about {
  border-left: 2px solid var(--accent);
  padding: 4px 0 4px 20px;
  margin: 0 0 56px;
  max-width: 680px;
}

.landing .about-label {
  font-family: 'Outfit', sans-serif;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 10px;
}

.landing .about p {
  font-size: 16px;
  color: var(--text-dim);
  line-height: 1.65;
  margin-bottom: 10px;
  max-width: none;
}

.landing .about p:last-of-type { margin-bottom: 0; }

.landing .about em { color: var(--text); font-style: normal; font-weight: 500; }

.landing .about-sig {
  font-size: 13px !important;
  color: var(--text-mute) !important;
  margin-top: 14px !important;
}

.toc-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 20px;
  margin-top: 32px;
}

.toc-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  text-decoration: none;
  transition: all 0.15s;
  display: block;
}

.toc-card:hover {
  border-color: var(--accent);
  transform: translateY(-2px);
  text-decoration: none;
}

.toc-card .num {
  font-family: 'Outfit', sans-serif;
  font-size: 12px;
  color: var(--accent);
  letter-spacing: 0.08em;
  font-weight: 600;
  margin-bottom: 8px;
  display: block;
}

.toc-card h3 {
  font-size: 18px;
  margin: 0 0 8px;
  color: var(--text);
}

.toc-card p {
  font-size: 14px;
  color: var(--text-dim);
  margin: 0;
}

/* ===== Responsive ===== */
@media (max-width: 1100px) {
  .layout { grid-template-columns: var(--sidebar-w) 1fr; }
  .toc { display: none; }
}

@media (max-width: 768px) {
  .layout { grid-template-columns: 1fr; }
  .sidebar {
    position: static;
    height: auto;
    border-right: none;
    border-bottom: 1px solid var(--border);
  }
  .main, .landing { padding: 40px 24px 80px; }
  h1 { font-size: 34px; }
  .landing h1 { font-size: 40px; }
  .toc-grid { grid-template-columns: 1fr; }
}