:root {
  --paper: #f3efe6;
  --paper-deep: #e7dfd1;
  --paper-bright: #fffdf8;
  --paper-blue: #dce8ee;
  --paper-amber: #f0dbc3;
  --paper-green: #dfe9df;
  --ink: #16243a;
  --ink-deep: #0c1828;
  --ink-soft: #53606d;
  --ink-faint: #737b82;
  --line: #c9beae;
  --line-dark: #aa9d8c;
  --blue: #315d75;
  --blue-deep: #24485f;
  --amber: #97451f;
  --amber-deep: #7c3e1e;
  --green: #3d675a;
  --red: #8c3b31;
  --white: #fffdf8;
  --shadow-sm: 5px 5px 0 rgba(117, 98, 76, .14);
  --shadow-md: 10px 10px 0 rgba(117, 98, 76, .16);
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", monospace;
  --sans: Inter, ui-sans-serif, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --serif: Iowan Old Style, Charter, "Source Serif 4", Georgia, serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  min-width: 280px;
  margin: 0;
  background:
    radial-gradient(circle at 8% 2%, rgba(49, 93, 117, .08), transparent 28rem),
    radial-gradient(circle at 96% 30%, rgba(185, 95, 45, .06), transparent 24rem),
    var(--paper);
  color: var(--ink);
  font-family: var(--sans);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
}

::selection { background: var(--paper-amber); color: var(--ink-deep); }
a { color: inherit; }
img, svg { max-width: 100%; height: auto; }
button, input { font: inherit; }
h1, h2, h3 { text-wrap: balance; }
[id] { scroll-margin-top: 110px; }
.shell { width: min(1180px, calc(100% - 48px)); margin-inline: auto; }
.visually-hidden {
  position: absolute !important;
  width: 1px !important;
  height: 1px !important;
  padding: 0 !important;
  margin: -1px !important;
  overflow: hidden !important;
  clip: rect(0, 0, 0, 0) !important;
  white-space: nowrap !important;
  border: 0 !important;
}

:focus-visible {
  outline: 3px solid var(--amber);
  outline-offset: 4px;
}

.skip-link {
  position: fixed;
  left: 16px;
  top: -120px;
  z-index: 110;
  padding: 11px 16px;
  background: var(--ink-deep);
  color: var(--white);
  font-weight: 750;
  text-decoration: none;
}
.skip-link:focus { top: 12px; }

.reading-progress {
  position: fixed;
  inset: 0 0 auto;
  z-index: 120;
  height: 4px;
  background: transparent;
  pointer-events: none;
}
.reading-progress span {
  display: block;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--amber), #d9914d);
  transform: scaleX(0);
  transform-origin: left center;
  will-change: transform;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  border-bottom: 1px solid rgba(170, 157, 140, .8);
  background: rgba(243, 239, 230, .92);
  backdrop-filter: blur(16px) saturate(110%);
}
.header-inner {
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 28px;
}
.site-mark {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}
.mark-glyph {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border: 1px solid var(--ink);
  border-radius: 50%;
  background: rgba(255, 253, 248, .5);
  font-family: var(--serif);
  font-size: 24px;
  font-style: italic;
  box-shadow: 3px 3px 0 var(--paper-deep);
}
.mark-copy { display: grid; line-height: 1.05; }
.mark-copy strong { font-family: var(--serif); font-size: 17px; }
.mark-copy small {
  color: var(--amber);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 700;
  letter-spacing: .17em;
  text-transform: uppercase;
}
.site-nav { display: flex; align-items: center; gap: 24px; }
.site-nav a {
  position: relative;
  padding-block: 7px;
  color: var(--ink-soft);
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}
.site-nav a::after {
  content: "";
  position: absolute;
  left: 0;
  right: 100%;
  bottom: 1px;
  height: 2px;
  background: var(--amber);
  transition: right .18s ease;
}
.site-nav a:hover,
.site-nav a[aria-current="page"] { color: var(--ink); }
.site-nav a:hover::after,
.site-nav a[aria-current="page"]::after { right: 0; }
.nav-toggle {
  display: none;
  border: 1px solid var(--line-dark);
  background: var(--paper-bright);
  color: var(--ink);
  padding: 8px 12px;
  font-weight: 750;
}

.eyebrow,
.card-index,
.toolbar-label,
.footer-kicker,
.rail-label,
.checkpoint-stage {
  margin: 0 0 16px;
  color: var(--amber);
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 750;
  letter-spacing: .16em;
  text-transform: uppercase;
}

.hero {
  position: relative;
  overflow: hidden;
  padding: 96px 0 84px;
  border-bottom: 1px solid var(--line);
}
.hero::before {
  content: "";
  position: absolute;
  inset: 0;
  opacity: .32;
  pointer-events: none;
  background-image: radial-gradient(circle, rgba(22, 36, 58, .18) 1px, transparent 1px);
  background-size: 26px 26px;
  mask-image: linear-gradient(90deg, transparent 8%, black 48%, transparent 96%);
}
.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.12fr) minmax(340px, .88fr);
  gap: 78px;
  align-items: center;
}
.hero h1 {
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(56px, 7vw, 94px);
  font-weight: 500;
  letter-spacing: -.06em;
  line-height: .91;
}
.hero h1 span,
.knowledge-hero h1 span { color: var(--amber); font-style: italic; }
.hero-lead {
  max-width: 700px;
  margin: 32px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(20px, 2vw, 25px);
  line-height: 1.46;
}
.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  margin-top: 36px;
}
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 47px;
  padding: 12px 19px;
  border: 1px solid var(--ink);
  text-decoration: none;
  font-size: 13px;
  font-weight: 750;
  transition: transform .16s ease, box-shadow .16s ease, background-color .16s ease;
}
.button.primary { background: var(--ink); color: var(--white); box-shadow: 5px 5px 0 var(--paper-deep); }
.button:hover { transform: translate(-2px, -2px); box-shadow: 5px 5px 0 var(--paper-deep); }
.button.secondary:hover { background: var(--paper-bright); }

.phase-portrait {
  position: relative;
  aspect-ratio: 1 / .82;
  border: 1px solid var(--line-dark);
  background: var(--paper-bright);
  overflow: hidden;
  box-shadow: 14px 14px 0 var(--paper-deep);
}
.phase-portrait::before,
.phase-portrait::after {
  content: "";
  position: absolute;
  width: 14px;
  height: 1px;
  background: var(--ink-soft);
}
.phase-portrait::before { left: 18px; top: 50%; }
.phase-portrait::after { left: 25px; top: calc(50% - 7px); width: 1px; height: 14px; }
.phase-grid {
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(rgba(49, 93, 117, .09) 1px, transparent 1px),
    linear-gradient(90deg, rgba(49, 93, 117, .09) 1px, transparent 1px);
  background-size: 34px 34px;
}
.orbit {
  position: absolute;
  left: 50%;
  top: 44%;
  border: 2px solid var(--blue);
  border-left-color: transparent;
  border-radius: 50%;
  transform: translate(-50%, -50%) rotate(-22deg);
}
.orbit::after {
  content: "";
  position: absolute;
  right: 5%;
  top: 15%;
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--amber);
  box-shadow: 0 0 0 5px rgba(185, 95, 45, .14);
}
.orbit-one { width: 76%; height: 48%; }
.orbit-two { width: 56%; height: 36%; opacity: .78; transform: translate(-50%, -50%) rotate(28deg); }
.orbit-three { width: 34%; height: 22%; opacity: .58; transform: translate(-50%, -50%) rotate(-12deg); }
.fixed-point {
  position: absolute;
  left: 50%;
  top: 44%;
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: var(--ink);
  transform: translate(-50%, -50%);
  box-shadow: 0 0 0 8px rgba(185, 95, 45, .2);
}
.phase-caption {
  position: absolute;
  inset: auto 18px 16px;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding-top: 10px;
  border-top: 1px solid var(--line);
  font-family: var(--mono);
  font-size: 9px;
}
.phase-caption span { color: var(--ink-soft); }

.learning-path {
  padding-block: 104px;
  border-bottom: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(255, 253, 248, .62), rgba(231, 223, 209, .38));
}
.section-heading {
  display: grid;
  grid-template-columns: .68fr 1.32fr;
  gap: 64px;
  align-items: start;
  margin-bottom: 46px;
}
.section-heading h2,
.compact-heading h2 {
  max-width: 780px;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(36px, 4vw, 56px);
  font-weight: 500;
  letter-spacing: -.04em;
  line-height: 1.08;
}
.section-deck {
  max-width: 700px;
  margin: 22px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: 19px;
}
.route-marker {
  display: inline-flex;
  gap: 9px;
  align-items: center;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 10px;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.route-marker b { color: var(--amber); }
.climb-route {
  position: relative;
  display: grid;
  gap: 12px;
  margin: 0;
  padding: 0;
  list-style: none;
}
.climb-route::before {
  content: "";
  position: absolute;
  left: 29px;
  top: 60px;
  bottom: 60px;
  width: 1px;
  background: linear-gradient(var(--blue), var(--amber));
}
.climb-stage {
  position: relative;
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr) auto;
  gap: 24px;
  align-items: center;
  min-height: 126px;
  padding: 24px 26px 24px 0;
  border: 1px solid var(--line);
  background: rgba(255, 253, 248, .78);
  box-shadow: 4px 4px 0 rgba(117, 98, 76, .08);
}
.climb-stage:nth-child(2) { margin-left: 2.5%; }
.climb-stage:nth-child(3) { margin-left: 5%; }
.climb-stage:nth-child(4) { margin-left: 7.5%; }
.climb-stage:nth-child(5) { margin-left: 10%; }
.stage-number {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 58px;
  height: 58px;
  margin-left: -1px;
  border: 1px solid var(--blue);
  border-radius: 50%;
  background: var(--paper-bright);
  color: var(--blue);
  font-family: var(--mono);
  font-size: 11px;
  font-weight: 800;
}
.climb-stage h3 { margin: 1px 0 3px; font-family: var(--serif); font-size: 27px; font-weight: 550; }
.climb-stage p { max-width: 700px; margin: 0; color: var(--ink-soft); }
.stage-altitude,
.stage-skill {
  color: var(--amber);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 750;
  letter-spacing: .13em;
  text-transform: uppercase;
}
.stage-skill { padding: 6px 9px; border: 1px solid var(--line); color: var(--ink-soft); background: var(--paper); }
.stage-frontier { border-color: rgba(185, 95, 45, .55); background: var(--paper-amber); }
.stage-frontier .stage-number { border-color: var(--amber); color: var(--amber); }
.learning-path-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-end;
  gap: 26px;
  margin-top: 30px;
}
.text-link { color: var(--blue-deep); font-size: 13px; font-weight: 800; text-underline-offset: 4px; }
.text-link span { color: var(--amber); }

.status-band { border-bottom: 1px solid var(--line); background: var(--ink); color: var(--white); }
.status-grid { display: grid; grid-template-columns: repeat(3, 1fr); }
.status-grid div { padding: 23px 28px; border-right: 1px solid rgba(255, 255, 255, .17); }
.status-grid div:first-child { padding-left: 0; }
.status-grid div:last-child { border-right: 0; }
.status-grid span {
  display: block;
  color: #b7c2cd;
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: .14em;
  text-transform: uppercase;
}
.status-grid strong { font-family: var(--serif); font-size: 18px; font-weight: 500; }

.pathways,
.proof-chain { padding-block: 96px; }
.pathway-grid,
.collection-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 18px; }
.pathway-card,
.collection-card {
  position: relative;
  min-height: 350px;
  display: flex;
  flex-direction: column;
  padding: 36px;
  border: 1px solid var(--line-dark);
  text-decoration: none;
  overflow: hidden;
  transition: transform .18s ease, box-shadow .18s ease;
}
.pathway-card::after,
.collection-card::after {
  content: "";
  position: absolute;
  right: -50px;
  bottom: -50px;
  width: 150px;
  height: 150px;
  border: 1px solid rgba(22, 36, 58, .12);
  border-radius: 50%;
  box-shadow: 0 0 0 28px rgba(22, 36, 58, .025), 0 0 0 56px rgba(22, 36, 58, .02);
}
.pathway-card:hover,
.collection-card:hover { transform: translate(-3px, -3px); box-shadow: var(--shadow-md); }
.notebook-card { background: var(--paper-blue); }
.knowledge-card { background: var(--paper-amber); }
.pathway-card h3,
.collection-card h2 { margin: 0; font-family: var(--serif); font-size: clamp(31px, 3vw, 39px); font-weight: 500; }
.pathway-card p,
.collection-card p { max-width: 510px; color: var(--ink-soft); }
.card-action { margin-top: auto; font-size: 12px; font-weight: 800; }
.card-action b { color: var(--amber); }
.collection-card-footer {
  display: flex;
  justify-content: space-between;
  gap: 18px;
  align-items: end;
  margin-top: auto;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
}
.proof-chain { border-top: 1px solid var(--line); }
.chain-list { margin: 0; padding: 0; list-style: none; border-top: 1px solid var(--line); }
.chain-list li {
  display: grid;
  grid-template-columns: 70px 1fr;
  gap: 20px;
  padding: 26px 0;
  border-bottom: 1px solid var(--line);
}
.chain-list > li > span { color: var(--amber); font-family: var(--mono); font-size: 11px; }
.chain-list strong { font-family: var(--serif); font-size: 24px; font-weight: 500; }
.chain-list p { margin: 4px 0 0; color: var(--ink-soft); }

.section-hero {
  position: relative;
  overflow: hidden;
  padding: 82px 0 64px;
  border-bottom: 1px solid var(--line);
  background:
    linear-gradient(135deg, rgba(220, 232, 238, .58), transparent 50%),
    var(--paper-deep);
}
.section-hero::after {
  content: "";
  position: absolute;
  right: -8vw;
  top: -18vw;
  width: 42vw;
  height: 42vw;
  border: 1px solid rgba(49, 93, 117, .18);
  border-radius: 50%;
  box-shadow: 0 0 0 58px rgba(49, 93, 117, .025), 0 0 0 116px rgba(49, 93, 117, .02);
}
.section-hero > .shell { position: relative; z-index: 1; }
.section-hero h1 {
  max-width: 940px;
  margin: 0;
  font-family: var(--serif);
  font-size: clamp(52px, 7vw, 86px);
  font-weight: 500;
  letter-spacing: -.055em;
  line-height: .96;
}
.section-hero > .shell > p:not(.eyebrow) {
  max-width: 790px;
  margin: 25px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(19px, 2.2vw, 23px);
}
.hero-facts {
  display: flex;
  flex-wrap: wrap;
  gap: 0;
  margin-top: 36px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 10px;
  text-transform: uppercase;
}
.hero-facts span { padding: 5px 18px; border-left: 1px solid var(--line-dark); }
.hero-facts span:first-child { padding-left: 0; border-left: 0; }
.hero-facts b { color: var(--amber); font-weight: 800; }
.section-body { padding-block: 62px 100px; }
.section-intro { max-width: 800px; margin-bottom: 48px; }
.section-intro > :first-child { margin-top: 0; }
.section-intro > :last-child { margin-bottom: 0; }
.knowledge-intro-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.35fr) minmax(260px, .65fr);
  gap: 70px;
  align-items: start;
  margin-bottom: 70px;
}
.knowledge-intro-grid .section-intro { margin-bottom: 0; }
.reader-promise {
  padding: 26px;
  border: 1px solid var(--line-dark);
  border-top: 4px solid var(--amber);
  background: var(--paper-bright);
  box-shadow: var(--shadow-sm);
}
.reader-promise p { margin: 0; color: var(--ink-soft); font-family: var(--serif); font-size: 18px; line-height: 1.55; }
.collection-intro { margin-top: 46px; }
.textbook-route { margin-bottom: 76px; padding: 46px; border: 1px solid var(--line); background: rgba(255, 253, 248, .58); }
.compact-heading { display: grid; grid-template-columns: .55fr 1.45fr; gap: 40px; align-items: start; margin-bottom: 38px; }
.textbook-route ol { display: grid; grid-template-columns: repeat(3, 1fr); gap: 0; margin: 0; padding: 0; list-style: none; }
.textbook-route li { display: grid; grid-template-columns: 34px 1fr; gap: 14px; padding: 20px 24px; border-left: 1px solid var(--line); }
.textbook-route li:first-child { padding-left: 0; border-left: 0; }
.textbook-route li > span { color: var(--amber); font-family: var(--mono); font-size: 10px; }
.textbook-route strong { font-family: var(--serif); font-size: 23px; font-weight: 550; }
.textbook-route p { margin: 4px 0 0; color: var(--ink-soft); font-size: 14px; }

.section-toolbar {
  display: flex;
  justify-content: space-between;
  align-items: end;
  gap: 24px;
  margin-bottom: 26px;
  padding-bottom: 13px;
  border-bottom: 1px solid var(--line-dark);
}
.section-toolbar > div { display: grid; }
.section-toolbar .toolbar-label { margin-bottom: 1px; }
.section-toolbar strong { font-family: var(--serif); font-size: 21px; font-weight: 550; }
.section-toolbar > span { color: var(--ink-soft); font-family: var(--mono); font-size: 10px; text-transform: uppercase; }
.back-link {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  color: var(--blue-deep);
  font-size: 13px;
  font-weight: 800;
  text-decoration: none;
}
.back-link:hover { text-decoration: underline; text-underline-offset: 4px; }

.entry-grid { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 18px; }
.entry-card { min-width: 0; }
.entry-card-link {
  position: relative;
  min-height: 330px;
  height: 100%;
  display: flex;
  flex-direction: column;
  padding: 30px;
  border: 1px solid var(--line-dark);
  background: rgba(255, 253, 248, .76);
  text-decoration: none;
  box-shadow: 4px 4px 0 rgba(117, 98, 76, .08);
  transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
}
.entry-card-link:hover { transform: translate(-3px, -3px); border-color: var(--blue); box-shadow: var(--shadow-md); }
.entry-card-topline { min-height: 27px; display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px; }
.level-badge,
.draft-badge {
  display: inline-flex;
  width: fit-content;
  align-items: center;
  padding: 4px 8px;
  border: 1px solid var(--line-dark);
  background: var(--paper-blue);
  color: var(--blue-deep);
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: .09em;
  text-transform: uppercase;
}
.draft-badge { border-color: #c89265; background: var(--paper-amber); color: var(--amber-deep); }
.entry-card.is-working-note .entry-card-link {
  border-style: dashed;
  background:
    repeating-linear-gradient(135deg, rgba(240, 219, 195, .16) 0, rgba(240, 219, 195, .16) 9px, transparent 9px, transparent 18px),
    rgba(255, 253, 248, .8);
}
.entry-card-copy { margin-top: 26px; }
.entry-card h2 { margin: 0; font-family: var(--serif); font-size: clamp(27px, 3vw, 35px); font-weight: 550; line-height: 1.12; }
.entry-card p { margin: 13px 0 0; color: var(--ink-soft); }
.entry-card-meta {
  margin-top: auto;
  padding-top: 28px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 9px;
  text-transform: uppercase;
}
.entry-card-details { display: flex; flex-wrap: wrap; align-items: center; gap: 7px 0; }
.entry-card-details > * + *::before { content: "/"; margin-inline: 10px; color: var(--line-dark); }
.entry-card-meta code { max-width: 100%; overflow-wrap: anywhere; color: var(--blue-deep); text-transform: none; }
.entry-card-action { width: 100%; margin-top: 14px; color: var(--ink); font-family: var(--sans); font-size: 12px; font-weight: 800; text-transform: none; }
.entry-card-action b { color: var(--amber); }
.empty-state { padding: 50px 4px; border-bottom: 1px solid var(--line); }
.empty-state-card { grid-column: 1 / -1; padding: 54px; border: 1px dashed var(--line-dark); background: rgba(255, 253, 248, .55); }
.empty-state span { color: var(--amber); font-family: var(--mono); font-size: 10px; letter-spacing: .13em; text-transform: uppercase; }
.empty-state h2 { margin: 11px 0; font-family: var(--serif); font-size: 34px; font-weight: 500; }
.empty-state p { max-width: 680px; color: var(--ink-soft); }

.glossary-filter { max-width: 760px; margin: 0 0 34px; }
.glossary-filter label { display: block; margin-bottom: 8px; font-family: var(--serif); font-size: 20px; font-weight: 600; }
.glossary-filter-control { position: relative; }
.glossary-filter-control input {
  width: 100%;
  min-height: 54px;
  padding: 13px 70px 13px 16px;
  border: 1px solid var(--line-dark);
  border-radius: 0;
  background: var(--paper-bright);
  color: var(--ink);
}
.glossary-filter-control input:focus { border-color: var(--blue); }
.glossary-filter-control > span {
  position: absolute;
  right: 17px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--amber);
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: .12em;
}
.glossary-grid { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; }
.glossary-card a {
  min-height: 142px;
  display: grid;
  grid-template-columns: 45px 1fr auto;
  gap: 20px;
  align-items: start;
  padding: 24px;
  border: 1px solid var(--line);
  background: rgba(255, 253, 248, .7);
  text-decoration: none;
  transition: border-color .16s ease, transform .16s ease, background-color .16s ease;
}
.glossary-card a:hover { border-color: var(--blue); background: var(--paper-bright); transform: translateY(-2px); }
.glossary-letter {
  display: grid;
  place-items: center;
  width: 42px;
  height: 42px;
  border: 1px solid var(--line-dark);
  border-radius: 50%;
  color: var(--amber);
  font-family: var(--serif);
  font-size: 22px;
  font-style: italic;
}
.glossary-card h2 { margin: 0; font-family: var(--serif); font-size: 25px; font-weight: 550; }
.glossary-card p { margin: 5px 0 0; color: var(--ink-soft); font-size: 14px; }
.glossary-arrow { color: var(--amber); font-family: var(--mono); font-size: 12px; }
.glossary-no-results { padding: 34px; border: 1px dashed var(--line-dark); color: var(--ink-soft); }

.article { max-width: 1240px; padding-block: 54px 110px; }
.article-header { max-width: 980px; margin-inline: auto; padding-bottom: 42px; border-bottom: 1px solid var(--line-dark); }
.breadcrumbs {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  align-items: center;
  margin-bottom: 44px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: .06em;
  text-transform: uppercase;
}
.breadcrumbs a { color: var(--blue-deep); text-underline-offset: 3px; }
.breadcrumbs span:last-child { max-width: 40ch; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.article-kicker-row { display: flex; justify-content: space-between; gap: 20px; align-items: center; }
.article-kicker-row .eyebrow { margin: 0; }
.article-header h1 {
  max-width: 940px;
  margin: 18px 0 0;
  font-family: var(--serif);
  font-size: clamp(48px, 7vw, 82px);
  font-weight: 500;
  letter-spacing: -.052em;
  line-height: .98;
}
.article-lead {
  max-width: 800px;
  margin: 27px 0 0;
  color: var(--ink-soft);
  font-family: var(--serif);
  font-size: clamp(20px, 2.5vw, 25px);
  line-height: 1.52;
}
.article-lead > :first-child { margin-top: 0; }
.article-lead > :last-child { margin-bottom: 0; }
.article-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 0;
  margin-top: 27px;
  color: var(--ink-soft);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: .06em;
  text-transform: uppercase;
}
.article-meta > * { padding: 0 13px; border-left: 1px solid var(--line-dark); }
.article-meta > *:first-child { padding-left: 0; border-left: 0; }
.article-orientation {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 1px;
  margin-top: 30px;
  border: 1px solid var(--line);
  background: var(--line);
}
.orientation-item { min-width: 0; padding: 18px 20px; background: rgba(255, 253, 248, .72); }
.article-orientation > .orientation-item:only-child { grid-column: 1 / -1; }
.orientation-item strong {
  display: block;
  margin-bottom: 8px;
  color: var(--amber);
  font-family: var(--mono);
  font-size: 9px;
  letter-spacing: .1em;
  text-transform: uppercase;
}
.orientation-values { display: flex; flex-wrap: wrap; gap: 6px; }
.orientation-values span { padding: 3px 7px; border: 1px solid var(--line); color: var(--ink-soft); font-size: 12px; }
.orientation-item code { color: var(--blue-deep); font-family: var(--mono); font-size: 12px; overflow-wrap: anywhere; }
.article-source-link { display: block; width: fit-content; margin-top: 9px; color: var(--blue-deep); font-size: 11px; font-weight: 800; text-underline-offset: 3px; }
.article-source-link span { color: var(--amber); }
.tag-list { display: flex; flex-wrap: wrap; gap: 7px; margin: 22px 0 0; padding: 0; list-style: none; }
.tag-list li { padding: 4px 8px; border: 1px solid var(--line); color: var(--ink-soft); font-family: var(--mono); font-size: 9px; text-transform: uppercase; }
.article-featured-image { max-width: 1040px; margin: 42px auto 0; }
.article-featured-image img { display: block; width: 100%; border: 1px solid var(--line-dark); background: var(--paper-bright); box-shadow: var(--shadow-md); }
.article-layout {
  display: grid;
  grid-template-columns: 230px minmax(0, 760px);
  justify-content: center;
  gap: 72px;
  align-items: start;
  margin-top: 48px;
}
.article-rail { position: sticky; top: 108px; min-width: 0; }
.rail-station { padding: 18px 0 22px; border-top: 3px solid var(--amber); border-bottom: 1px solid var(--line); }
.rail-station .rail-label { display: block; margin-bottom: 4px; }
.rail-station strong { font-family: var(--serif); font-size: 20px; font-weight: 550; }
.rail-station p { margin: 7px 0 0; color: var(--ink-soft); font-size: 12px; }
.toc { margin-top: 22px; border: 0; background: transparent; }
.toc summary {
  cursor: pointer;
  color: var(--ink);
  font-family: var(--mono);
  font-size: 10px;
  font-weight: 800;
  letter-spacing: .11em;
  text-transform: uppercase;
}
.toc nav > ul { margin: 15px 0 0; padding: 0; list-style: none; }
.toc ul ul { margin: 5px 0 0 12px; padding: 0; list-style: none; }
.toc li { margin: 0; }
.toc a {
  display: block;
  padding: 6px 0 6px 12px;
  border-left: 1px solid var(--line);
  color: var(--ink-soft);
  font-size: 11px;
  line-height: 1.35;
  text-decoration: none;
  overflow-wrap: anywhere;
}
.toc code { overflow-wrap: anywhere; }
.toc a:hover,
.toc a[aria-current="location"] { border-left: 3px solid var(--amber); padding-left: 10px; color: var(--ink); }
.article-main { min-width: 0; }
.article-body {
  min-width: 0;
  max-width: 100%;
  overflow-x: hidden;
  overflow-x: clip;
}
.key-result {
  position: relative;
  margin-bottom: 38px;
  padding: 28px 30px 28px 35px;
  border: 1px solid var(--line-dark);
  border-left: 5px solid var(--amber);
  background: var(--paper-amber);
  box-shadow: var(--shadow-sm);
}
.key-result > span { color: var(--amber-deep); font-family: var(--mono); font-size: 9px; font-weight: 800; letter-spacing: .13em; text-transform: uppercase; }
.key-result > div { margin-top: 8px; font-family: var(--serif); font-size: 19px; }
.key-result code { overflow-wrap: anywhere; word-break: break-word; }
.key-result p:first-child { margin-top: 0; }
.key-result p:last-child { margin-bottom: 0; }
.article-footer {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: end;
  margin-top: 76px;
  padding-top: 24px;
  border-top: 1px solid var(--line-dark);
  color: var(--ink-soft);
  font-size: 12px;
}
.article-footer .footer-kicker { display: block; margin-bottom: 4px; }
.article-footer p { margin: 0; }
.article-footer a { color: var(--blue-deep); font-weight: 750; text-underline-offset: 3px; }
.chapter-nav { display: grid; grid-template-columns: repeat(2, 1fr); gap: 12px; margin-top: 28px; }
.chapter-nav-link { min-height: 118px; padding: 20px; border: 1px solid var(--line); background: rgba(255, 253, 248, .6); text-decoration: none; }
.chapter-nav-link.next { text-align: right; grid-column: 2; }
.chapter-nav-link span { display: block; margin-bottom: 7px; color: var(--amber); font-family: var(--mono); font-size: 9px; letter-spacing: .1em; text-transform: uppercase; }
.chapter-nav-link strong { font-family: var(--serif); font-size: 18px; font-weight: 550; }
.chapter-nav-link:hover { border-color: var(--blue); background: var(--paper-bright); }

.prose { font-family: var(--serif); font-size: 18.5px; line-height: 1.78; }
.prose > :first-child { margin-top: 0; }
.prose p { margin-block: 1.15em; }
.prose h2,
.prose h3,
.prose h4 {
  position: relative;
  color: var(--ink-deep);
  font-family: var(--sans);
  line-height: 1.2;
}
.prose h2 { margin: 2.7em 0 .8em; padding-top: .72em; border-top: 1px solid var(--line); font-size: 31px; letter-spacing: -.025em; }
.prose h3 { margin: 2.2em 0 .65em; font-size: 23px; letter-spacing: -.015em; }
.prose h4 { margin: 1.9em 0 .55em; font-size: 18px; }
.heading-anchor {
  position: absolute;
  right: calc(100% + 10px);
  color: var(--line-dark);
  font-family: var(--mono);
  font-size: .6em;
  font-weight: 500;
  text-decoration: none;
  opacity: 0;
}
.prose h2:hover .heading-anchor,
.prose h3:hover .heading-anchor,
.prose h4:hover .heading-anchor,
.heading-anchor:focus { opacity: 1; }
.prose a { color: var(--blue-deep); text-decoration-thickness: 1px; text-underline-offset: 3px; }
.prose a:hover { color: var(--amber-deep); }
.prose strong { color: var(--ink-deep); font-weight: 750; }
.prose ul,
.prose ol { padding-left: 1.4em; }
.prose li { margin-block: .42em; padding-left: .2em; }
.prose li::marker { color: var(--amber); font-family: var(--mono); font-weight: 750; }
.prose hr { margin-block: 3.2em; border: 0; border-top: 1px solid var(--line-dark); }
.prose blockquote {
  margin: 2em 0;
  padding: 4px 0 4px 24px;
  border-left: 4px solid var(--amber);
  color: var(--ink-soft);
  font-size: 1.03em;
  font-style: italic;
}
.prose code {
  padding: .14em .32em;
  border: 1px solid rgba(170, 157, 140, .55);
  background: var(--paper-deep);
  color: var(--ink-deep);
  font-family: var(--mono);
  font-size: .8em;
  overflow-wrap: anywhere;
}
.prose pre,
.highlight pre {
  margin: 0;
  overflow-x: auto;
  padding: 28px 24px;
  border: 0;
  background: var(--ink-deep);
  color: #edf2f7;
  font-family: var(--mono);
  font-size: 13px;
  line-height: 1.65;
  tab-size: 2;
}
.prose > pre { margin-block: 30px; }
.prose pre code { padding: 0; border: 0; background: none; color: inherit; font-size: inherit; overflow-wrap: normal; }
.highlight,
.code-block { position: relative; margin-block: 30px; border: 1px solid #26364a; background: var(--ink-deep); box-shadow: var(--shadow-sm); }
.highlight pre { margin: 0; }
.copy-code {
  position: absolute;
  z-index: 2;
  top: 9px;
  right: 9px;
  padding: 5px 8px;
  border: 1px solid #5e6b7a;
  background: #15253a;
  color: #dce4ed;
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 750;
  letter-spacing: .08em;
  text-transform: uppercase;
  cursor: pointer;
}
.copy-code:hover { border-color: #a8b8c8; background: #213750; }
.highlight .chroma { color: #e5e9ef; background: var(--ink-deep); }
.highlight .c,
.highlight .c1,
.highlight .cm { color: #92a3ad; font-style: italic; }
.highlight .k,
.highlight .kc,
.highlight .kd,
.highlight .kn { color: #f0b47d; }
.highlight .s,
.highlight .s1,
.highlight .s2 { color: #b8d59e; }
.highlight .nf,
.highlight .nb { color: #9bc8e0; }
.highlight .mi,
.highlight .mf { color: #e8c88f; }
.highlight .o { color: #d9a9cb; }

.table-scroll {
  position: relative;
  overflow-x: auto;
  margin-block: 34px;
  border: 1px solid var(--line-dark);
  background: var(--paper-bright);
  box-shadow: var(--shadow-sm);
  scrollbar-color: var(--amber) var(--paper-deep);
}
.table-scroll:focus-visible { outline-offset: 3px; }
.prose table { width: 100%; min-width: 580px; border-collapse: collapse; font-family: var(--sans); font-size: 13px; line-height: 1.52; }
.prose th,
.prose td { padding: 13px 15px; border-right: 1px solid var(--line); border-bottom: 1px solid var(--line); text-align: left; vertical-align: top; }
.prose th:last-child,
.prose td:last-child { border-right: 0; }
.prose tr:last-child td { border-bottom: 0; }
.prose th { background: var(--paper-deep); color: var(--ink-deep); font-size: 11px; letter-spacing: .04em; }
.prose tbody tr:nth-child(even) { background: rgba(231, 223, 209, .28); }
.prose caption { padding: 11px 14px; color: var(--ink-soft); text-align: left; font-family: var(--serif); font-style: italic; }

.panel {
  display: grid;
  grid-template-columns: 118px minmax(0, 1fr);
  gap: 24px;
  margin-block: 34px;
  padding: 24px;
  border: 1px solid var(--line-dark);
  border-left: 5px solid var(--blue);
  background: var(--paper-blue);
  font-family: var(--sans);
  font-size: 14px;
  line-height: 1.62;
  box-shadow: var(--shadow-sm);
}
.panel-label { padding-top: 2px; }
.panel-label,
.panel-body { min-width: 0; }
.panel-label span { color: var(--blue-deep); font-family: var(--mono); font-size: 9px; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
.panel-body > :first-child { margin-top: 0; }
.panel-body > :last-child { margin-bottom: 0; }
.panel-body h3 { margin-top: 0; font-size: 18px; }
.panel-warning { border-left-color: var(--amber); background: var(--paper-amber); }
.panel-warning .panel-label span { color: var(--amber-deep); }
.panel-definition,
.panel-theorem { border-left-color: var(--green); background: var(--paper-green); }
.panel-definition .panel-label span,
.panel-theorem .panel-label span { color: var(--green); }
.panel-theorem { border-top: 3px double var(--green); }
.panel-proof { border-left-color: var(--ink-soft); background: rgba(255, 253, 248, .82); }
.panel-proof .panel-label span { color: var(--ink-soft); }
.panel-proof .panel-body::after { content: "□"; float: right; color: var(--ink); font-family: var(--mono); }
.panel-intuition { border-left-color: var(--amber); background: linear-gradient(135deg, var(--paper-amber), var(--paper-bright)); }
.panel-intuition .panel-label span { color: var(--amber-deep); }
.panel-exercise,
.panel-checkpoint { border-left-color: var(--blue); border-style: dashed; background: rgba(220, 232, 238, .52); }
.panel-quote { border-left-color: var(--line-dark); background: var(--paper-bright); }

.lean-bridge {
  margin-block: 42px;
  border: 1px solid var(--line-dark);
  background: linear-gradient(145deg, rgba(220, 232, 238, .7), rgba(255, 253, 248, .95));
  box-shadow: var(--shadow-md);
}
.lean-bridge-header {
  display: flex;
  justify-content: space-between;
  gap: 20px;
  padding: 16px 20px;
  border-bottom: 1px solid var(--line-dark);
  background: var(--ink-deep);
  color: #edf2f7;
  font-family: var(--sans);
}
.lean-bridge-header span,
.lean-bridge-kicker,
.repo-check-heading span,
.repo-check-command > span {
  font-family: var(--mono);
  font-size: 9px;
  font-weight: 800;
  letter-spacing: .11em;
  text-transform: uppercase;
}
.lean-bridge-header span { color: #efbd78; }
.lean-bridge-header strong { font-size: 13px; }
.lean-bridge-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); }
.lean-bridge-layer { min-width: 0; padding: 22px; border-right: 1px solid var(--line); }
.lean-bridge-layer:last-child { border-right: 0; }
.lean-bridge-kicker { display: block; margin-bottom: 12px; color: var(--blue-deep); }
.lean-bridge-layer > div > :first-child,
.lean-bridge-map > div > :first-child,
.repo-check-body > :first-child { margin-top: 0; }
.lean-bridge-layer > div > :last-child,
.lean-bridge-map > div > :last-child,
.repo-check-body > :last-child { margin-bottom: 0; }
.lean-bridge-human { background: rgba(255, 253, 248, .82); }
.lean-bridge-paper { background: rgba(243, 235, 220, .72); }
.lean-bridge-code { background: var(--ink-deep); color: #edf2f7; }
.lean-bridge-code .lean-bridge-kicker { color: #efbd78; }
.lean-bridge-code pre { margin: 0; padding: 0; background: transparent; white-space: pre-wrap; }
.lean-bridge-code code { border: 0; background: transparent; color: inherit; overflow-wrap: anywhere; }
.lean-bridge-map { padding: 20px 22px; border-top: 1px solid var(--line-dark); background: var(--paper-blue); }

.repo-check {
  margin-block: 42px;
  border: 1px solid var(--line-dark);
  border-top: 4px solid var(--green);
  background: var(--paper-bright);
  box-shadow: var(--shadow-md);
}
.repo-check-heading { display: grid; gap: 7px; padding: 20px 22px; border-bottom: 1px solid var(--line); }
.repo-check-heading span { color: var(--green); }
.repo-check-heading strong { color: var(--ink-deep); font-family: var(--mono); font-size: 13px; overflow-wrap: anywhere; }
.repo-check-body { padding: 20px 22px 0; }
.repo-check-command { margin: 20px 22px; border: 1px solid #26364a; background: var(--ink-deep); color: #edf2f7; }
.repo-check-command > span { display: block; padding: 12px 16px 0; color: #efbd78; }
.repo-check-command pre { margin: 0; padding: 16px; white-space: pre-wrap; }
.repo-check-command code { border: 0; background: transparent; color: inherit; }
.repo-check-boundary { margin: 0; padding: 16px 22px; border-top: 1px solid var(--line); background: var(--paper-amber); color: var(--ink-soft); font-family: var(--sans); font-size: 13px; }

.reference-figure,
.diagram { margin: 44px 0; }
.reference-figure-frame,
.diagram-frame { padding: 12px; border: 1px solid var(--line-dark); background: var(--paper-bright); box-shadow: var(--shadow-md); }
.reference-figure img { display: block; width: 100%; background: var(--paper-bright); }
.reference-figure-wide .reference-figure-frame { overflow-x: auto; overscroll-behavior-inline: contain; }
.reference-figure-wide img { min-width: 680px; }
.reference-figure figcaption,
.diagram figcaption {
  margin-top: 16px;
  color: var(--ink-soft);
  font-family: var(--sans);
  font-size: 13px;
  line-height: 1.6;
}
.reference-figure figcaption > span { display: block; margin-bottom: 5px; color: var(--amber); font-family: var(--mono); font-size: 9px; font-weight: 800; letter-spacing: .11em; text-transform: uppercase; }
.reference-figure figcaption p,
.diagram figcaption p { margin: 0; }
.mermaid { display: flex; justify-content: center; margin: 0; overflow-x: auto; padding: 18px; background: var(--paper-bright); color: var(--ink); }
.mermaid svg { min-width: 500px; }

.learning-checkpoint {
  display: grid;
  grid-template-columns: 68px minmax(0, 1fr);
  gap: 26px;
  margin: 48px 0;
  padding: 30px;
  border: 1px solid var(--line-dark);
  background: linear-gradient(135deg, var(--paper-blue), rgba(255, 253, 248, .82));
  box-shadow: var(--shadow-md);
}
.checkpoint-marker { display: flex; justify-content: center; }
.checkpoint-marker span { position: relative; display: block; width: 34px; height: 34px; margin-top: 5px; border: 2px solid var(--blue); border-radius: 50%; background: var(--paper-bright); }
.checkpoint-marker span::after { content: ""; position: absolute; left: 50%; top: 100%; width: 1px; height: 70px; background: linear-gradient(var(--blue), transparent); }
.checkpoint-stage { display: block; margin-bottom: 6px; color: var(--blue-deep); }
.checkpoint-content h2 { margin: 0 0 10px; padding: 0; border: 0; font-family: var(--serif); font-size: 27px; font-weight: 550; }
.checkpoint-content > div > :first-child { margin-top: 0; }
.checkpoint-content > div > :last-child { margin-bottom: 0; }

.katex-display { max-width: 100%; overflow-x: auto; overflow-y: hidden; padding: 10px 2px; }
.katex { font-size: 1.04em; }
.term-link { text-decoration-style: dotted; text-decoration-thickness: 2px; }
.figure-note { margin-top: -28px; color: var(--ink-soft); font-family: var(--sans); font-size: 13px; }

.site-footer { border-top: 1px solid var(--line-dark); background: var(--paper-deep); }
.footer-inner { min-height: 154px; display: flex; align-items: center; justify-content: space-between; gap: 40px; }
.footer-statement { max-width: 520px; }
.footer-statement .footer-kicker { display: block; margin-bottom: 4px; }
.footer-statement p { margin: 0; font-family: var(--serif); font-size: 18px; }
.footer-inner nav { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 19px; }
.footer-inner a { color: var(--ink-soft); font-size: 12px; font-weight: 700; text-decoration: none; }
.footer-inner a:hover { color: var(--amber-deep); text-decoration: underline; text-underline-offset: 4px; }

@media (max-width: 1040px) {
  .site-nav { gap: 16px; }
  .article-layout { grid-template-columns: 190px minmax(0, 720px); gap: 44px; }
  .climb-stage:nth-child(n) { margin-left: 0; }
}

@media (max-width: 860px) {
  .shell { width: min(100% - 32px, 1180px); }
  .header-inner { min-height: 68px; }
  .nav-toggle { display: block; }
  .site-nav {
    position: absolute;
    left: 0;
    right: 0;
    top: 100%;
    display: none;
    padding: 18px 20px;
    border-bottom: 1px solid var(--line-dark);
    background: var(--paper);
    flex-direction: column;
    align-items: flex-start;
    box-shadow: 0 12px 20px rgba(22, 36, 58, .12);
  }
  .site-nav.is-open { display: flex; }
  .no-js .nav-toggle { display: none; }
  .no-js .header-inner { flex-wrap: wrap; padding-block: 12px; }
  .no-js .site-nav { position: static; width: 100%; display: flex; flex-wrap: wrap; padding: 0; border: 0; background: transparent; box-shadow: none; flex-direction: row; }
  .hero { padding-top: 64px; }
  .hero-grid { grid-template-columns: 1fr; gap: 50px; }
  .phase-portrait { width: min(100%, 600px); }
  .section-heading,
  .compact-heading { grid-template-columns: 1fr; gap: 12px; }
  .climb-stage { grid-template-columns: 58px 1fr; }
  .stage-skill { display: none; }
  .status-grid { grid-template-columns: 1fr; }
  .status-grid div,
  .status-grid div:first-child { padding: 16px 0; border-right: 0; border-bottom: 1px solid rgba(255, 255, 255, .17); }
  .status-grid div:last-child { border-bottom: 0; }
  .knowledge-intro-grid { grid-template-columns: 1fr; gap: 32px; }
  .textbook-route ol { grid-template-columns: 1fr; }
  .textbook-route li,
  .textbook-route li:first-child { padding: 18px 0; border-left: 0; border-top: 1px solid var(--line); }
  .textbook-route li:first-child { border-top: 0; }
  .article-layout { grid-template-columns: 1fr; gap: 30px; }
  .article-rail { position: static; }
  .rail-station { display: none; }
  .toc { margin: 0; padding: 18px 20px; border: 1px solid var(--line); background: var(--paper-bright); }
  .toc nav { columns: 2; column-gap: 28px; }
  .article-header { max-width: 100%; }
  .heading-anchor { right: auto; left: calc(100% + 8px); }
}

@media (max-width: 680px) {
  .hero h1 { font-size: clamp(49px, 15vw, 66px); }
  .learning-path,
  .pathways,
  .proof-chain { padding-block: 70px; }
  .climb-route::before { left: 23px; }
  .climb-stage { grid-template-columns: 46px 1fr; gap: 18px; padding: 21px 18px 21px 0; }
  .stage-number { width: 46px; height: 46px; }
  .climb-stage h3 { font-size: 24px; }
  .pathway-grid,
  .collection-grid,
  .entry-grid,
  .glossary-grid { grid-template-columns: 1fr; }
  .pathway-card,
  .collection-card { min-height: 300px; padding: 28px; }
  .textbook-route { padding: 28px 24px; }
  .hero-facts { display: grid; }
  .hero-facts span,
  .hero-facts span:first-child { padding: 6px 0; border: 0; }
  .section-hero { padding: 62px 0 48px; }
  .section-body { padding-block: 48px 76px; }
  .entry-card-link { min-height: 300px; padding: 26px; }
  .empty-state-card { padding: 38px 28px; }
  .article { padding-top: 34px; }
  .breadcrumbs { margin-bottom: 32px; }
  .article-header h1 { font-size: clamp(43px, 14vw, 65px); }
  .article-orientation { grid-template-columns: 1fr; }
  .article-meta > * { padding-inline: 9px; }
  .toc nav { columns: 1; }
  .panel { grid-template-columns: minmax(0, 1fr); gap: 8px; padding: 21px; }
  .lean-bridge-grid { grid-template-columns: 1fr; }
  .lean-bridge-layer { border-right: 0; border-bottom: 1px solid var(--line); }
  .lean-bridge-layer:last-child { border-bottom: 0; }
  .lean-bridge-header { display: grid; gap: 5px; }
  .panel-label { padding-bottom: 8px; border-bottom: 1px solid rgba(22, 36, 58, .18); }
  .learning-checkpoint { grid-template-columns: 42px 1fr; gap: 16px; padding: 24px 20px; }
  .checkpoint-marker span { width: 28px; height: 28px; }
  .chapter-nav { grid-template-columns: 1fr; }
  .chapter-nav-link.next { grid-column: auto; text-align: left; }
  .article-footer,
  .footer-inner { align-items: flex-start; flex-direction: column; justify-content: center; }
  .footer-inner { padding-block: 34px; }
  .footer-inner nav { justify-content: flex-start; }
}

@media (max-width: 480px) {
  .shell { width: min(100% - 24px, 1180px); }
  .mark-copy small { display: none; }
  .hero-actions { align-items: stretch; flex-direction: column; }
  .button { width: 100%; }
  .phase-caption { align-items: flex-start; flex-direction: column; gap: 2px; }
  .learning-path-actions { justify-content: flex-start; flex-direction: column; gap: 12px; }
  .section-toolbar { align-items: flex-start; flex-direction: column; }
  .glossary-card a { grid-template-columns: 38px 1fr; gap: 15px; }
  .glossary-letter { width: 36px; height: 36px; }
  .glossary-arrow { display: none; }
  .article-kicker-row { align-items: flex-start; flex-direction: column-reverse; }
  .article-meta { display: grid; gap: 6px; }
  .article-meta > * { padding: 0; border: 0; }
  .prose { font-size: 17.5px; }
  .prose h2 { font-size: 27px; }
  .heading-anchor { display: none; }
  .reference-figure-frame,
  .diagram-frame { padding: 6px; }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition-duration: .001ms !important;
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
  }
}

@media print {
  :root { --paper: white; --paper-deep: #f1f1f1; --paper-bright: white; --ink: black; --ink-deep: black; }
  body { background: white; color: black; }
  .site-header,
  .site-footer,
  .reading-progress,
  .article-rail,
  .chapter-nav,
  .copy-code { display: none !important; }
  .article { max-width: none; padding: 0; }
  .article-layout { display: block; }
  .article-header { max-width: none; }
  .article-main { max-width: none; }
  .prose a { color: black; text-decoration: underline; }
  .panel,
  .reference-figure-frame,
  .diagram-frame,
  .table-scroll { box-shadow: none; break-inside: avoid; }
}