@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=Inter+Tight:wght@600;700&family=JetBrains+Mono:wght@400;500&display=swap');

:root {
  color-scheme: light;
  --bg: #F7F4EE;
  --surface: #FFFDF9;
  --surface-alt: #F1ECE3;
  --sidebar-bg: color-mix(in srgb, #FFFDF9 92%, #F7F4EE);
  --text: #1E2430;
  --text-muted: #556070;
  --border: #DED7CB;
  --accent: #C75A2C;
  --accent-dark: #9E431F;
  --link: #2563EB;
  --success: #2E7D5A;
  --radius: 4px;
  --radius-card: 6px;
  --radius-pill: 999px;
  --shadow: 0 1px 3px rgba(0,0,0,0.07);
  --shadow-md: 0 2px 8px rgba(0,0,0,0.09);
  --callout-bg: #1a2035;
  --callout-text: #F4EEE5;
  --callout-muted: rgba(244, 238, 229, 0.8);
  --accent-soft: rgba(199, 90, 44, 0.1);
  --link-soft: rgba(37, 99, 235, 0.1);
  --success-soft: rgba(46, 125, 90, 0.12);
}

@media (prefers-color-scheme: dark) {
  :root {
    color-scheme: dark;
    --bg: #11151B;
    --surface: #171D26;
    --surface-alt: #202734;
    --sidebar-bg: #141922;
    --text: #ECE7DE;
    --text-muted: #A9B1BD;
    --border: #2C3442;
    --accent: #E67A4A;
    --accent-dark: #F19A70;
    --link: #7AA2FF;
    --shadow: 0 1px 3px rgba(0,0,0,0.25);
    --shadow-md: 0 2px 8px rgba(0,0,0,0.35);
    --callout-bg: var(--surface-alt);
    --callout-text: var(--text);
    --callout-muted: var(--text-muted);
    --accent-soft: rgba(230, 122, 74, 0.14);
    --link-soft: rgba(122, 162, 255, 0.14);
    --success-soft: rgba(46, 125, 90, 0.14);
  }
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  background: var(--bg);
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: 'Inter', system-ui, sans-serif;
  font-size: 17px;
  line-height: 1.7;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

img,
svg,
iframe {
  max-width: 100%;
}

a {
  color: var(--link);
  text-decoration-thickness: 1px;
  text-underline-offset: 0.15em;
}

a:hover {
  color: var(--accent-dark);
}

h1, h2, h3, h4, h5, h6,
p, ul, ol, dl, blockquote, pre, figure, table {
  margin-top: 0;
}

h1,
h2 {
  font-family: 'Inter Tight', 'Inter', sans-serif;
  letter-spacing: -0.04em;
}

h1 {
  margin-bottom: 18px;
  font-size: clamp(40px, 5vw, 64px);
  font-weight: 700;
  line-height: 0.98;
  overflow-wrap: anywhere;
}

h2 {
  margin-bottom: 14px;
  font-size: clamp(24px, 3vw, 36px);
  font-weight: 650;
  line-height: 1.08;
  overflow-wrap: anywhere;
}

h3 {
  margin-bottom: 8px;
  font-size: 19px;
  font-weight: 600;
  line-height: 1.3;
}

h4,
h5,
h6,
strong,
dt,
summary {
  color: var(--text);
}

p,
li,
dd,
td,
label,
input,
button,
textarea,
select {
  color: var(--text-muted);
  font-size: 1rem;
}

li + li {
  margin-top: 0.35rem;
}

code,
pre {
  font-family: 'JetBrains Mono', monospace;
}

code {
  padding: 0.12rem 0.35rem;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  font-size: 0.92em;
}

pre {
  overflow-x: auto;
  padding: 16px 20px;
  background: var(--callout-bg);
  border: 1px solid color-mix(in srgb, var(--callout-bg) 82%, var(--border));
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  color: var(--callout-text);
}

pre code {
  padding: 0;
  background: transparent;
  border: 0;
  color: inherit;
}

::selection {
  background: var(--accent-soft);
}

:focus-visible {
  outline: 2px solid var(--link);
  outline-offset: 2px;
}

.site-wrapper {
  min-height: 100vh;
}

.sidebar {
  position: fixed;
  top: 0;
  left: 0;
  width: 240px;
  max-width: 240px;
  height: 100vh;
  overflow-y: auto;
  padding: 16px 0;
  background: var(--sidebar-bg);
  border-right: 1px solid var(--border);
}

.sidebar-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 16px 10px;
}

.wordmark {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--text);
  font-size: 15px;
  font-weight: 600;
  text-decoration: none;
}

.wordmark svg {
  color: var(--accent);
  flex-shrink: 0;
}

.sidebar-body {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.nav-group {
  display: flex;
  flex-direction: column;
  gap: 2px;
  margin: 0;
  padding: 0;
  background: transparent;
  border: 0;
  border-radius: 0;
}

.nav-group + .nav-group {
  margin-top: 10px;
}

.nav-group-label {
  margin-top: 20px;
  padding: 0 16px 4px;
  color: var(--text-muted);
  font-size: 10px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.sidebar a {
  display: block;
  padding: 6px 16px;
  border-radius: var(--radius);
  color: var(--text-muted);
  font-size: 14px;
  text-decoration: none;
}

.sidebar a:hover {
  background: var(--surface-alt);
  color: var(--text);
}

.sidebar a.active {
  color: var(--accent);
  font-weight: 600;
}

.content-area {
  min-height: 100vh;
  margin-left: 240px;
  padding: 0 24px 64px;
}

.content-area > *,
.page-layout > *,
main > *,
.panel,
.card,
.concept-card,
.path-card,
.scenario-card,
.callout,
.offramp,
.lab-card,
.catalog-filters,
.filter-group,
.filter-pills {
  min-width: 0;
}

.mobile-topbar,
.sidebar-close,
.sidebar-backdrop {
  display: none;
}

.mobile-topbar {
  gap: 12px;
}

.mobile-topbar .wordmark {
  min-width: 0;
  flex: 1 1 auto;
}

.mobile-topbar .wordmark span {
  white-space: nowrap;
}

.hamburger,
.sidebar-close {
  flex: 0 0 auto;
}

.hero,
main,
.catalog-filters {
  width: min(1100px, 100%);
  margin: 0 auto;
}

.hero {
  padding: 44px 0 16px;
}

.hero.compact {
  padding-top: 40px;
}

.page-layout {
  display: grid;
  grid-template-columns: minmax(0, 760px) 180px;
  column-gap: 64px;
  align-items: start;
  width: min(1100px, 100%);
  margin: 0 auto;
}

.page-layout > .hero,
.page-layout > main {
  width: 100%;
  margin: 0;
}

.page-layout > .hero {
  grid-column: 1;
}

.page-layout > main {
  grid-column: 1;
}

.page-toc {
  grid-column: 2;
  grid-row: 1 / 3;
  position: sticky;
  top: 80px;
  align-self: start;
}

.page-toc nav {
  padding: 0;
  background: transparent;
  border: 0;
  box-shadow: none;
}

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

.page-toc li + li {
  margin-top: 8px;
}

.page-toc a {
  display: block;
  padding-left: 14px;
  border-left: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 14px;
  text-decoration: none;
}

.page-toc a:hover,
.page-toc a.active {
  border-left-color: var(--accent);
  color: var(--accent);
}

main {
  padding-bottom: 48px;
}

section {
  margin: 40px 0;
  scroll-margin-top: 88px;
}

main > :first-child {
  margin-top: 16px;
}

.eyebrow,
.path-kicker,
.scenario-input,
.toc-label,
.depth-label,
.offramp-kicker,
.filter-label,
.lab-nav-label,
.sketch-label,
.scenario-input {
  color: var(--accent);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
}

.lede {
  color: var(--text-muted);
  font-size: clamp(19px, 2vw, 24px);
  line-height: 1.65;
}

.hero-note {
  margin-top: 0.75rem;
  font-size: 0.9rem;
  color: var(--text-muted);
  opacity: 0.7;
  font-style: italic;
}

.hero .lede,
.section-heading,
.panel > :where(p, ul, ol, dl, .lede, .fit, .examples),
.card > :where(p, ul, ol, dl, .fit, .examples),
.callout > :where(p, ul, ol, dl),
.note,
.offramp-meta,
.lab-card > div > :where(p, ul, ol),
.walk-step p,
.timeline li > :where(p, ul, ol),
.concept-card > :where(p, ul, ol, dl) {
  max-width: 760px;
}

.panel,
.catalog-filters,
details:not(.depth-section):not(.code-preview),
.coverage-map,
.system-sketch,
.choice-wheel,
.diagram-shell,
.wide-table-wrapper {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

.panel {
  padding: clamp(16px, 2.5vw, 24px);
}

.section-heading {
  margin-bottom: 20px;
}

.note {
  margin: 18px 0;
  padding: 14px 16px;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
}

.callout {
  padding: 16px 20px;
  background: var(--callout-bg);
  border: 1px solid color-mix(in srgb, var(--callout-bg) 80%, var(--border));
  border-left: 3px solid var(--accent);
  border-radius: var(--radius);
  color: var(--callout-text);
  box-shadow: var(--shadow);
}

.callout h2,
.callout h3,
.callout h4,
.callout strong,
.callout summary {
  color: var(--callout-text);
}

.callout p,
.callout li,
.callout em,
.callout span,
.callout .fit,
.callout .examples {
  color: var(--callout-muted);
}

.search-shell {
  display: grid;
  gap: 24px;
}

.search-panel {
  padding: clamp(18px, 2.5vw, 28px);
}

.search-panel .pagefind-ui {
  --pagefind-ui-scale: 0.95;
  --pagefind-ui-primary: var(--accent);
  --pagefind-ui-text: var(--text);
  --pagefind-ui-background: var(--surface);
  --pagefind-ui-border: var(--border);
  --pagefind-ui-tag: var(--surface-alt);
  --pagefind-ui-font: 'Inter', system-ui, sans-serif;
}

.search-panel .pagefind-ui__search-input,
.search-panel .pagefind-ui__result {
  box-shadow: none;
}

.search-panel .pagefind-ui__message,
.search-panel .pagefind-ui__result-excerpt {
  color: var(--text-muted);
}

.search-panel .pagefind-ui__result-link {
  font-weight: 600;
}

.cards,
.path-grid,
.scenario-grid,
.quick-map,
.learning-path,
.visual-stack,
.walkthrough,
.stack,
.lab-list,
.concept-grid,
.comparison-grid,
.experiment-list,
.two-column,
.three-columns {
  display: grid;
  gap: 16px;
}

.cards-2,
.concept-grid,
.two-column {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.cards-3,
.path-grid,
.scenario-grid,
.three-columns {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.quick-map,
.comparison-grid {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}

.learning-path {
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
}

.experiment-list {
  grid-template-columns: repeat(5, minmax(0, 1fr));
}

.card,
.concept-card,
.path-card,
.scenario-card,
.quick-map a,
.learning-path a,
.visual-layer,
.sketch-card,
.choice-card,
.behavior-rail,
.branch-card,
.walk-step,
.stack-layer,
.timeline li,
.lab-card,
.node,
.comparison-grid article,
.experiment-list article,
.two-column > div,
.three-columns > div,
.coverage-row > *,
.offramp,
.decision-card {
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
  box-shadow: none;
}

.card,
.concept-card,
.path-card,
.scenario-card,
.quick-map a,
.learning-path a,
.visual-layer,
.sketch-card,
.choice-card,
.branch-card,
.walk-step,
.stack-layer,
.lab-card,
.offramp,
.decision-card {
  padding: 16px;
}

.card,
.concept-card {
  border-left: 3px solid transparent;
}

.path-card,
.scenario-card,
.quick-map a,
.learning-path a,
.visual-layer,
.sketch-card,
.choice-card,
.branch-card,
.offramp,
.decision-card,
.lab-nav-prev,
.lab-nav-next,
.glossary-jumpbar a,
.filter-pill,
.sidebar a,
summary,
details.code-preview > summary {
  transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.path-card,
.scenario-card,
.quick-map a,
.learning-path a,
.visual-layer,
.sketch-card,
.choice-card,
.branch-card,
.offramp,
.decision-card,
.node,
.comparison-grid article {
  color: inherit;
  text-decoration: none;
}

.path-card:hover,
.scenario-card:hover,
.quick-map a:hover,
.learning-path a:hover,
.visual-layer:hover,
.sketch-card:hover,
.choice-card:hover,
.branch-card:hover,
.offramp:hover,
.decision-card:hover,
.node:hover,
.comparison-grid article:hover {
  transform: translateY(-1px);
  border-color: color-mix(in srgb, var(--accent) 45%, var(--border));
}

.card[data-lifecycle="emerging"],
.concept-card[data-lifecycle="emerging"] {
  border-left-color: #D97706;
}

.card[data-lifecycle="default"],
.concept-card[data-lifecycle="default"] {
  border-left-color: #2563EB;
}

.card[data-lifecycle="stable"],
.concept-card[data-lifecycle="stable"] {
  border-left-color: #2E7D5A;
}

.card[data-lifecycle="declining"],
.concept-card[data-lifecycle="declining"] {
  border-left-color: #9CA3AF;
}

.card[data-lifecycle="niche"],
.concept-card[data-lifecycle="niche"] {
  border-left-color: #D97706;
}

.card[data-lifecycle="absorbed"],
.concept-card[data-lifecycle="absorbed"] {
  border-left-color: var(--accent);
}

.card[data-lifecycle="legacy"],
.concept-card[data-lifecycle="legacy"] {
  border-left-color: #9CA3AF;
}

.fit,
.examples {
  color: var(--text-muted);
  font-size: 15px;
}

.tag-row,
.filter-pills,
.glossary-jumpbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.tag,
.filter-pill,
details.code-preview > summary,
.glossary-jumpbar a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 28px;
  padding: 2px 8px;
  border: 1px solid var(--border);
  border-radius: var(--radius-pill);
  background: var(--surface-alt);
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 600;
  text-decoration: none;
}

.tag.default { color: #1D4ED8; }
.tag.niche { color: #B45309; }
.tag.absorbed { color: var(--accent-dark); }
.tag.legacy { color: #6B7280; }

.filter-pill {
  cursor: pointer;
  font-family: inherit;
}

.filter-pill:hover,
.glossary-jumpbar a:hover,
details.code-preview > summary:hover {
  border-color: var(--accent);
  color: var(--accent-dark);
}

.filter-pill.active {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.filter-reset {
  margin-left: auto;
  padding: 0;
  border: 0;
  background: transparent;
  color: var(--text-muted);
  font: inherit;
  font-size: 14px;
  cursor: pointer;
  text-decoration: underline;
  text-underline-offset: 0.16em;
}

.filter-reset:hover {
  color: var(--accent-dark);
}

.catalog-filters {
  position: sticky;
  top: 16px;
  z-index: 10;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 12px 18px;
  margin-bottom: 24px;
  padding: 14px 16px;
}

.filter-group {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

.path-card,
.scenario-card,
.quick-map a,
.learning-path a {
  display: grid;
  gap: 8px;
}

.quick-map a,
.learning-path a {
  min-height: 132px;
}

.path-card strong,
.scenario-card strong,
.quick-map strong,
.learning-path strong,
.offramp strong,
.visual-layer strong,
.sketch-card strong,
.choice-card strong,
.branch-card strong {
  display: block;
  font-size: 18px;
  line-height: 1.3;
}

.intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.45fr) minmax(280px, 0.85fr);
  gap: 24px;
  align-items: start;
}

.lede-section,
.author-section,
.about-section {
  max-width: 760px;
}

.author-section {
  padding-top: 8px;
  border-top: 1px solid var(--border);
}

.author-section p:last-child,
.lede-section p:last-child,
.about-section p:last-child {
  margin-bottom: 0;
}

.learning-path a span,
.walk-step > span,
.timeline li::before,
.lab-number {
  display: inline-grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border: 1px solid var(--border);
  border-radius: 50%;
  background: var(--surface);
  color: var(--accent);
  font-size: 14px;
  font-weight: 700;
}

.visual-stack,
.sketch-column,
.coverage-map,
.walkthrough,
.stack,
.timeline,
.glossary {
  gap: 12px;
}

.visual-layer {
  display: grid;
  grid-template-columns: 52px minmax(0, 0.9fr) minmax(0, 1fr);
  gap: 16px;
  align-items: center;
}

.visual-layer.governance,
.visual-layer.runtime,
.visual-layer.capabilities,
.sketch-card.tool,
.branch-card.action,
.branch-card.coordinate {
  border-left: 3px solid var(--accent);
}

.visual-layer.orchestration,
.visual-layer.packaging,
.visual-layer.foundation,
.sketch-card.model,
.sketch-card.host,
.branch-card.context,
.branch-card.decide {
  border-left: 3px solid var(--link);
}

.visual-layer.hosts,
.visual-layer.protocols,
.sketch-card.protocol,
.sketch-card.governance,
.branch-card.connect,
.branch-card.package {
  border-left: 3px solid var(--success);
}

.system-sketch,
.choice-wheel,
.diagram-shell,
.coverage-map {
  overflow-x: auto;
  padding: 16px;
}

.system-sketch {
  display: grid;
  grid-template-columns: minmax(220px, 1fr) 32px minmax(240px, 1.1fr) 32px minmax(220px, 1fr);
  align-items: center;
}

.sketch-card {
  display: grid;
  gap: 6px;
  min-height: 118px;
}

.sketch-card span,
.choice-card span,
.branch-card span {
  color: var(--text-muted);
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.sketch-arrow,
.arrow {
  color: var(--text-muted);
  font-size: 22px;
  font-weight: 700;
  text-align: center;
}

.agent-loop-card,
.choice-center,
.branch-root,
.decision-root,
.node.primary {
  background: var(--callout-bg);
  border: 1px solid color-mix(in srgb, var(--callout-bg) 80%, var(--border));
  color: var(--callout-text);
  border-radius: var(--radius);
}

.agent-loop-card {
  display: grid;
  gap: 14px;
  justify-items: center;
  min-height: 360px;
  padding: 20px;
  text-align: center;
}

.agent-loop-card .sketch-label,
.agent-loop-card em,
.decision-root span:last-child,
.branch-root span,
.node.primary span {
  color: var(--callout-muted);
}

.loop-ring {
  position: relative;
  display: grid;
  place-items: center;
  width: min(240px, 100%);
  aspect-ratio: 1;
  border: 2px solid color-mix(in srgb, var(--callout-text) 24%, transparent);
  border-radius: 50%;
}

.loop-ring::after {
  content: '';
  width: 34%;
  aspect-ratio: 1;
  border-radius: 50%;
  background: color-mix(in srgb, var(--callout-text) 15%, transparent);
}

.loop-ring span {
  position: absolute;
  padding: 4px 8px;
  border-radius: var(--radius-pill);
  background: var(--surface);
  color: var(--text);
  font-size: 11px;
  font-weight: 700;
}

.loop-ring span:nth-child(1) { top: 10px; }
.loop-ring span:nth-child(2) { right: -8px; }
.loop-ring span:nth-child(3) { bottom: 10px; }
.loop-ring span:nth-child(4) { left: -8px; }

.behavior-rail {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  border-style: dashed;
}

.choice-wheel {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
}

.choice-card,
.choice-center {
  min-height: 136px;
  text-align: center;
}

.choice-center {
  display: grid;
  place-items: center;
  border-radius: 50%;
  font-size: 20px;
  line-height: 1.15;
}

.branch-map {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 18px 12px;
}

.branch-root {
  grid-column: 1 / -1;
  justify-self: center;
  width: min(360px, 100%);
  padding: 18px;
  text-align: center;
  border-radius: var(--radius-pill);
}

.branch-card {
  display: grid;
  align-content: center;
  gap: 8px;
  min-height: 150px;
  text-align: center;
}

.coverage-legend {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  align-items: center;
  min-width: 860px;
  color: var(--text-muted);
  font-size: 14px;
}

.coverage-legend span {
  display: inline-flex;
  align-items: center;
  gap: 8px;
}

.legend-dot,
.coverage-dot::before {
  content: '';
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--link);
}

.legend-dot.strong,
.coverage-dot.strong::before {
  width: 14px;
  height: 14px;
  background: var(--accent);
}

.coverage-row {
  display: grid;
  grid-template-columns: minmax(150px, 1.05fr) repeat(5, minmax(120px, 1fr));
  gap: 8px;
  align-items: stretch;
  min-width: 860px;
}

.coverage-row > * {
  min-height: 56px;
  padding: 12px;
}

.coverage-head > span {
  background: var(--surface-alt);
  color: var(--text);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  text-align: center;
}

.coverage-head > span:first-child {
  text-align: left;
}

.coverage-row > a {
  color: var(--text);
  font-weight: 600;
  text-decoration: none;
}

.coverage-dot {
  display: grid;
  place-items: center;
  gap: 6px;
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 600;
  text-align: center;
}

.coverage-empty,
.legend-empty {
  color: color-mix(in srgb, var(--text-muted) 72%, transparent);
}

.diagram {
  display: grid;
  grid-template-columns: 1fr auto 1fr auto 1fr;
  gap: 12px;
  align-items: center;
  margin: 24px 0;
}

.node {
  display: grid;
  place-items: center;
  min-height: 120px;
  padding: 18px;
  text-align: center;
  font-size: 18px;
  font-weight: 600;
}

.node span {
  display: block;
  margin-top: 6px;
  color: var(--text-muted);
  font-size: 14px;
  font-weight: 500;
}

.node.accent {
  border-left: 3px solid var(--accent);
}

.walk-step {
  display: grid;
  grid-template-columns: 44px minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

.stack-layer {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 16px;
}

.layer-number {
  color: var(--accent);
  font-family: 'Inter Tight', 'Inter', sans-serif;
  font-size: 28px;
  font-weight: 700;
  line-height: 1;
}

.timeline {
  padding: 0;
  list-style: none;
  counter-reset: timeline;
}

.timeline li {
  position: relative;
  padding: 18px 18px 18px 70px;
  counter-increment: timeline;
}

.timeline li::before {
  content: counter(timeline);
  position: absolute;
  top: 16px;
  left: 18px;
}

.lab-card {
  display: grid;
  grid-template-columns: 64px minmax(0, 1fr);
  gap: 18px;
  border-left: 3px solid var(--accent);
}

.lab-card:nth-child(3n + 2) {
  border-left-color: var(--link);
}

.lab-card:nth-child(3n) {
  border-left-color: var(--success);
}

.lab-number {
  width: 44px;
  height: 44px;
}

.lab-nav {
  display: flex;
  align-items: stretch;
  justify-content: space-between;
  gap: 12px;
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
}

.lab-nav-prev,
.lab-nav-next {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 12px 14px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: inherit;
  text-decoration: none;
}

.lab-nav-prev:hover,
.lab-nav-next:hover {
  background: var(--surface-alt);
  border-color: var(--accent);
}

.lab-nav-next {
  text-align: right;
}

.lab-nav-title,
.lab-nav-index {
  color: var(--text);
  font-size: 14px;
  font-weight: 600;
}

.lab-nav-index {
  flex: 0 0 auto;
  align-self: center;
  color: var(--text-muted);
  text-decoration: none;
}

table {
  width: 100%;
  border-collapse: collapse;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.wide-table-wrapper {
  overflow-x: auto;
  padding: 0;
}

.wide-table-wrapper table,
.comparison-table {
  min-width: 900px;
}

th,
td {
  padding: 14px 16px;
  border-bottom: 1px solid var(--border);
  text-align: left;
  vertical-align: top;
}

th {
  background: var(--surface-alt);
  color: var(--text);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

tr:last-child td {
  border-bottom: 0;
}

details {
  margin-top: 16px;
}

summary {
  cursor: pointer;
  font-weight: 600;
}

details:not(.depth-section):not(.code-preview) {
  padding: 14px 16px;
}

details:not(.depth-section):not(.code-preview) > summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  list-style: none;
}

details:not(.depth-section):not(.code-preview) > summary::-webkit-details-marker,
details.depth-section > summary::-webkit-details-marker,
details.code-preview > summary::-webkit-details-marker {
  display: none;
}

details:not(.depth-section):not(.code-preview) > summary::after {
  content: '+';
  color: var(--accent);
  font-size: 18px;
  line-height: 1;
}

details:not(.depth-section):not(.code-preview)[open] > summary::after {
  content: '−';
}

details.depth-section {
  margin: 28px 0;
}

details.depth-section > summary {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 16px 18px;
  background: var(--surface-alt);
  border: 1px solid var(--border);
  border-radius: var(--radius-card);
}

details.depth-section[open] > summary {
  border-bottom-left-radius: 0;
  border-bottom-right-radius: 0;
}

details.depth-section > summary::after {
  content: 'Expand';
  color: var(--text-muted);
  font-size: 12px;
  font-weight: 500;
}

details.depth-section[open] > summary::after {
  content: 'Collapse';
}

details.code-preview pre {
  margin: 10px 0 8px;
  max-height: 320px;
  overflow-y: auto;
  font-size: 13px;
}

.offramp {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.offramp-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.offramp-desc {
  color: var(--text-muted);
  font-size: 15px;
}

.offramp-arrow {
  color: var(--text-muted);
  font-size: 24px;
  flex-shrink: 0;
}

.glossary-jumpbar {
  margin-bottom: 24px;
}

.glossary-jumpbar a.disabled,
.disabled {
  opacity: 0.4;
  pointer-events: none;
}

.glossary-letter {
  margin: 32px 0 14px;
  padding-bottom: 6px;
  border-bottom: 1px solid var(--border);
  color: var(--accent);
  font-size: 18px;
  font-weight: 700;
}

.glossary-search {
  width: min(100%, 400px);
  margin-bottom: 18px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  color: var(--text);
  font: inherit;
}

.glossary dt {
  margin-top: 18px;
  font-weight: 600;
}

.glossary dd {
  margin-left: 0;
  padding-bottom: 16px;
  border-bottom: 1px solid var(--border);
}

.plain-list {
  padding-left: 1.1rem;
}

.card.filtered-out,
.catalog-section.all-hidden {
  display: none;
}

@media (max-width: 1199px) {
  .quick-map,
  .comparison-grid,
  .experiment-list {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .page-layout {
    grid-template-columns: minmax(0, 1fr) 160px;
    column-gap: 40px;
  }
}

@media (max-width: 1023px) {
  .mobile-topbar {
    position: sticky;
    top: 0;
    z-index: 120;
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 12px 16px;
    background: color-mix(in srgb, var(--bg) 92%, transparent);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(10px);
  }

  .hamburger,
  .sidebar-close {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 36px;
    height: 36px;
    padding: 0;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--text);
    cursor: pointer;
    font: inherit;
    font-size: 18px;
  }

  .sidebar {
    z-index: 200;
    width: 280px;
    max-width: 280px;
    transform: translateX(-100%);
    transition: transform 0.24s ease;
    background: var(--surface);
    box-shadow: var(--shadow-md);
    pointer-events: none;
  }

  .sidebar.open {
    transform: translateX(0);
    pointer-events: auto;
  }

  .sidebar-backdrop {
    position: fixed;
    inset: 0;
    z-index: 180;
    background: rgba(17, 21, 27, 0.45);
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.24s ease;
  }

  .sidebar-backdrop.open {
    display: block;
    opacity: 1;
    pointer-events: auto;
  }

  .content-area {
    margin-left: 0;
    padding: 0 20px 56px;
  }

  .page-layout {
    display: block;
  }

  .page-toc {
    display: none;
  }

  .catalog-filters {
    top: 68px;
  }

  .intro-grid,
  .system-sketch,
  .diagram,
  .choice-wheel,
  .branch-map,
  .lab-nav {
    grid-template-columns: 1fr;
  }

  .cards-3,
  .path-grid,
  .scenario-grid,
  .quick-map,
  .comparison-grid,
  .experiment-list,
  .three-columns {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .behavior-rail {
    flex-direction: column;
    align-items: flex-start;
  }

  .lab-nav {
    display: grid;
  }

  .lab-nav-index {
    order: -1;
    justify-self: start;
    margin-bottom: 2px;
  }
}

@media (max-width: 720px) {
  body {
    font-size: 16px;
    overflow-x: hidden;
  }

  .content-area {
    padding: 0 16px 48px;
  }

  h1 {
    font-size: clamp(34px, 9vw, 42px);
    line-height: 1.02;
  }

  .hero {
    padding: 36px 0 24px;
  }

  .cards-2,
  .cards-3,
  .path-grid,
  .scenario-grid,
  .quick-map,
  .learning-path,
  .concept-grid,
  .comparison-grid,
  .experiment-list,
  .two-column,
  .three-columns,
  .intro-grid,
  .lab-card,
  .walk-step,
  .stack-layer,
  .visual-layer {
    grid-template-columns: 1fr;
  }

  .timeline li {
    padding-left: 18px;
    padding-top: 66px;
  }

  .timeline li::before {
    left: 18px;
  }

  .offramp {
    flex-direction: column;
    align-items: flex-start;
  }

  .filter-reset {
    margin-left: 0;
    align-self: flex-start;
  }

  .catalog-filters {
    position: static;
    align-items: stretch;
    gap: 14px;
  }

  .filter-group {
    flex-direction: column;
    align-items: stretch;
    gap: 10px;
  }

  .filter-pills {
    width: 100%;
    flex-wrap: nowrap;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .filter-pill {
    flex: 0 0 auto;
  }

  .lab-nav {
    gap: 10px;
  }

  .lab-nav-prev,
  .lab-nav-next {
    min-width: 0;
    text-align: left;
  }

  .wide-table-wrapper,
  table {
    display: block;
    max-width: 100%;
    overflow-x: auto;
  }
}