:root {
  --bg: #f4f7fb;
  --panel: #ffffff;
  --line: #d9e2ec;
  --ink: #152235;
  --muted: #62748a;
  --accent: #2267d8;
  --accent-soft: #eaf1ff;
  --accent-strong: #0f4db8;
  --ok: #12725b;
  --ok-soft: #e7f8f0;
  --warn: #8b5e00;
  --warn-soft: #fff4d8;
  --shadow: 0 18px 38px rgba(21, 34, 53, 0.08);
}

* {
  box-sizing: border-box;
}

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: "Segoe UI", "Yu Gothic UI", sans-serif;
  max-width: 100%;
  overflow-x: hidden;
}

a {
  color: inherit;
}

a:focus-visible,
button:focus-visible {
  outline: 3px solid var(--accent-strong);
  outline-offset: 3px;
}

body {
  min-height: 100vh;
  background:
    radial-gradient(circle at top left, rgba(34, 103, 216, 0.12), transparent 34%),
    linear-gradient(180deg, #f7f9fc 0%, #eef3f9 100%);
}

.landing {
  width: min(1180px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 30px 0 98px;
}

.hero-shell {
  position: relative;
  padding: 30px 32px 24px;
  border: 1px solid rgba(21, 34, 53, 0.04);
  border-radius: 36px;
  background: linear-gradient(145deg, rgba(255, 255, 255, 0.99) 0%, rgba(245, 249, 255, 0.97) 100%);
  box-shadow: 0 18px 38px rgba(21, 34, 53, 0.06);
}

.hero-shell::before {
  content: "";
  position: absolute;
  inset: 0 auto auto 0;
  width: 42%;
  height: 100%;
  border-radius: 36px;
  background: linear-gradient(180deg, rgba(34, 103, 216, 0.04), transparent 78%);
  pointer-events: none;
}

.hero-grid {
  position: relative;
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(300px, 0.75fr);
  gap: 28px;
  align-items: stretch;
}

.hero-copy {
  padding: 12px 8px 6px;
}

.hero-note {
  margin: 0 0 14px;
  color: var(--accent-strong);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero-copy h1 {
  margin: 0;
  max-width: 660px;
  font-size: clamp(36px, 4.2vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.03em;
}

.hero-lead {
  margin-top: 16px;
  max-width: 630px;
}

.hero-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
  margin-top: 28px;
}

.hero-clarity-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  min-width: 0;
  min-height: 100%;
  padding: 28px;
  border: 1px solid rgba(34, 103, 216, 0.16);
  border-radius: 24px;
  background: linear-gradient(160deg, rgba(234, 241, 255, 0.92), rgba(255, 255, 255, 0.86));
}

.hero-clarity-eyebrow,
.concept-label {
  margin: 0 0 10px;
  color: var(--accent-strong);
  font-size: 13px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero-clarity-card h2 {
  max-width: 12ch;
  margin: 0;
  font-size: clamp(28px, 3vw, 40px);
  line-height: 1.08;
  letter-spacing: -0.025em;
}

.hero-clarity-card h2 a,
.hero-clarity-link {
  color: var(--accent-strong);
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.hero-clarity-card p:not(.hero-clarity-eyebrow) {
  max-width: 34ch;
  margin: 18px 0 0;
  color: var(--muted);
  line-height: 1.65;
}

.hero-clarity-link {
  margin-top: 24px;
  font-weight: 800;
}

.canonical-concept {
  border: 1px solid rgba(34, 103, 216, 0.18);
  border-radius: 16px;
  padding: 20px 22px 20px 0;
  background: rgba(234, 241, 255, 0.5);
}

.canonical-concept .concept-label {
  margin-bottom: 6px;
}

.primary-button,
.secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 54px;
  padding: 0 22px;
  border-radius: 16px;
  font-size: 16px;
  font-weight: 800;
  text-decoration: none;
  transition: transform 140ms ease, box-shadow 140ms ease, border-color 140ms ease;
}

.primary-button {
  background: #0f4db8;
  color: #ffffff;
  box-shadow: 0 14px 30px rgba(15, 77, 184, 0.22);
}

.secondary-button {
  border: 1px solid rgba(21, 34, 53, 0.12);
  background: rgba(255, 255, 255, 0.88);
  color: var(--ink);
}

.primary-button:hover,
.secondary-button:hover {
  transform: translateY(-1px);
}

.hero-panel {
  display: flex;
  flex-direction: column;
  min-width: 0;
  padding-top: 2px;
}

.flow-board {
  display: grid;
  gap: 8px;
  width: 100%;
  padding: 8px 0 0;
  border: 0;
  border-radius: 0;
  background: transparent;
}

.flow-row {
  display: grid;
  align-items: center;
  justify-content: center;
  gap: 10px;
}

.flow-row-top,
.flow-row-middle {
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
}

.flow-row-bottom {
  grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
}

.flow-node {
  min-height: 56px;
  display: grid;
  place-items: center;
  padding: 10px 12px;
  border: 1px solid rgba(113, 138, 170, 0.16);
  border-radius: 15px;
  background: rgba(255, 255, 255, 0.72);
  color: #445a74;
  font-size: 13px;
  font-weight: 700;
  line-height: 1.25;
  text-align: center;
  min-width: 0;
}

.flow-node-split {
  background: rgba(242, 247, 255, 0.8);
}

.flow-node-strong {
  border-color: rgba(118, 162, 243, 0.48);
  background: rgba(237, 244, 255, 0.96);
  color: #0f4db8;
  font-weight: 800;
}

.flow-connector,
.flow-drop {
  color: #6f86a3;
  font-size: 17px;
  font-weight: 600;
  text-align: center;
}

.flow-caption {
  margin: 12px 2px 0;
  color: #435a75;
  font-size: 13px;
  line-height: 1.45;
  font-weight: 700;
}

.landing-section {
  margin-top: 56px;
}

.landing-section + .landing-section {
  margin-top: 76px;
}

.section-heading {
  display: grid;
  gap: 10px;
  margin-bottom: 22px;
}

.section-heading h2 {
  margin: 0;
  font-size: clamp(28px, 3vw, 36px);
  line-height: 1.08;
}

.section-heading p {
  margin: 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.65;
}

.catalog-filter {
  display: inline-flex;
  gap: 8px;
  margin-bottom: 24px;
  padding: 6px;
  border: 1px solid rgba(21, 34, 53, 0.06);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.72);
}

.filter-button {
  min-height: 42px;
  padding: 0 16px;
  border: 0;
  border-radius: 12px;
  background: transparent;
  color: #51657d;
  font-size: 14px;
  font-weight: 800;
  cursor: pointer;
}

.filter-button.is-active {
  background: #0f4db8;
  color: #ffffff;
}

.catalog-grid {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 20px;
}

.featured-rail {
  display: grid;
  grid-template-columns: minmax(0, 1.18fr) minmax(280px, 0.82fr);
  gap: 20px;
  align-items: start;
}

.operating-rationale {
  display: grid;
  grid-template-columns: minmax(0, 1fr) 44px minmax(0, 1fr);
  gap: 22px;
  align-items: center;
  margin: 0 0 30px;
  padding: 28px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.rationale-column { min-width: 0; }
.rationale-column h3 { margin: 8px 0 14px; font-size: clamp(23px, 2.4vw, 31px); line-height: 1.16; }
.rationale-column ul { margin: 0; padding-left: 22px; color: var(--muted); font-size: 16px; line-height: 1.55; }
.rationale-label { margin: 0; color: var(--blue); font-size: 13px; font-weight: 800; letter-spacing: 0; text-transform: uppercase; }
.rationale-connector { color: var(--blue); font-size: 36px; font-weight: 800; text-align: center; }

.trait-grid {
  display: grid;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  gap: 14px;
}

.trait-item {
  min-width: 0;
  padding: 20px 16px;
  border-top: 3px solid rgba(34, 103, 216, 0.45);
  background: rgba(255, 255, 255, 0.46);
}

.trait-item span { color: var(--blue); font-size: 13px; font-weight: 800; }
.trait-item p { margin: 10px 0 0; color: #435a75; font-size: 15px; line-height: 1.5; }

.mechanism-map {
  display: grid;
  border-top: 1px solid var(--line);
}

.mechanism-row {
  display: grid;
  grid-template-columns: minmax(240px, 0.8fr) minmax(0, 1.4fr);
  gap: 28px;
  padding: 18px 0;
  border-bottom: 1px solid var(--line);
}

.mechanism-row strong { font-size: 17px; }
.mechanism-row span { color: var(--muted); font-size: 16px; line-height: 1.5; }

.routing-note,
.improvement-note {
  margin: 22px 0 0;
  padding: 18px 20px;
  border-left: 4px solid var(--blue);
  background: rgba(255, 255, 255, 0.58);
  color: #435a75;
  font-size: 16px;
  line-height: 1.55;
}

.improvement-flow {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 18px;
}

.improvement-flow > div {
  min-width: 0;
  padding: 22px;
  border: 1px solid rgba(21, 34, 53, 0.08);
  border-radius: 18px;
  background: rgba(255, 255, 255, 0.72);
}

.improvement-flow strong { display: block; margin-bottom: 10px; font-size: 19px; }
.improvement-flow span { color: var(--muted); font-size: 15px; line-height: 1.5; }

.entry-path-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  border-top: 1px solid var(--line);
}

.entry-path {
  min-width: 0;
  padding: 24px 24px 26px 0;
  border-bottom: 1px solid var(--line);
}

.entry-path:nth-child(even) {
  padding-right: 0;
  padding-left: 24px;
  border-left: 1px solid var(--line);
}

.entry-path-level {
  color: var(--blue);
  font-size: 13px;
  font-weight: 800;
}

.entry-path h3 {
  margin: 10px 0 8px;
  font-size: 22px;
  line-height: 1.25;
}

.entry-path p {
  margin: 0 0 16px;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.55;
}

.entry-path a,
.catalog-directory-links a {
  color: #0f4db8;
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
}

.entry-path a:hover,
.catalog-directory-links a:hover {
  text-decoration: underline;
}

.entry-path-links,
.catalog-directory-links {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
}

.catalog-directory-links {
  align-items: center;
  margin-top: 22px;
  padding: 18px 20px;
  background: rgba(255, 255, 255, 0.58);
}

.catalog-directory-links span {
  margin-right: auto;
  color: var(--muted);
  font-size: 15px;
}

.catalog-card {
  display: grid;
  gap: 12px;
  grid-column: span 2;
  padding: 22px 22px 20px;
  border: 1px solid rgba(21, 34, 53, 0.05);
  border-radius: 26px;
  background: rgba(255, 255, 255, 0.84);
  box-shadow: 0 14px 30px rgba(21, 34, 53, 0.05);
}

.catalog-card-last-row-wide {
  grid-column: span 3;
}

.featured-card {
  display: grid;
  gap: 12px;
  padding: 20px 22px 18px;
  border: 1px solid rgba(21, 34, 53, 0.05);
  border-radius: 24px;
  background: linear-gradient(180deg, rgba(248, 251, 255, 0.92) 0%, rgba(255, 255, 255, 0.96) 100%);
  box-shadow: 0 16px 34px rgba(21, 34, 53, 0.05);
}

.featured-card-primary {
  min-height: 100%;
}

.featured-steps {
  display: grid;
  gap: 12px;
  padding-top: 4px;
  align-self: stretch;
  justify-content: stretch;
}

.featured-step-item {
  display: grid;
  gap: 8px;
  align-content: start;
  padding: 10px 2px 10px 16px;
  border-left: 1px solid rgba(34, 103, 216, 0.14);
}

.featured-step-item-top {
  display: flex;
  align-items: center;
  gap: 10px;
}

.featured-step-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 24px;
  height: 24px;
  border-radius: 999px;
  background: rgba(34, 103, 216, 0.1);
  color: #0f4db8;
  font-size: 12px;
  font-weight: 800;
}

.featured-step-item h3 {
  margin: 0;
  font-size: 18px;
  line-height: 1.18;
}

.featured-step-item p {
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  line-height: 1.5;
}

.featured-step {
  color: #58708c;
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.featured-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.featured-card h3 {
  margin: 0;
  font-size: 28px;
  line-height: 1.12;
}

.featured-card p {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.58;
}

.featured-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.featured-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #0f4db8;
  font-size: 14px;
  font-weight: 800;
  text-decoration: none;
}

.featured-inline-link {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  color: #0f4db8;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
}

.featured-link::after,
.featured-inline-link::after {
  content: "→";
}

.featured-link:hover,
.featured-inline-link:hover {
  text-decoration: underline;
}

.catalog-card.is-filtered-out {
  display: none !important;
}

.catalog-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}

.catalog-deck,
.catalog-lang {
  display: inline-flex;
  align-items: center;
  min-height: 30px;
  padding: 0 11px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 800;
}

.catalog-deck {
  background: #edf4ff;
  color: #0f4db8;
}

.catalog-lang {
  border: 1px solid rgba(113, 138, 170, 0.18);
  color: #51657d;
}

.catalog-card h3 {
  margin: 0;
  font-size: 24px;
  line-height: 1.15;
}

.catalog-summary {
  margin: 0;
  color: var(--muted);
  font-size: 15px;
  line-height: 1.58;
}

.catalog-meta-line {
  margin: -2px 0 0;
  color: #58708c;
  font-size: 13px;
  line-height: 1.5;
}

.catalog-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}

.open-deck-button {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 0;
  border: 0;
  background: transparent;
  color: #183250;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  transition: color 140ms ease;
}

.open-deck-button:hover {
  color: #0f4db8;
  text-decoration: underline;
}

.open-deck-button::after {
  content: "";
}

.page {
  width: min(1120px, calc(100vw - 48px));
  max-width: 100%;
  margin: 0 auto;
  padding: 40px 0 72px;
}

.page-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 16px;
}

.page-header a {
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.page-header a:hover {
  text-decoration: underline;
}

.hero {
  padding: 36px 0 28px;
}

.eyebrow {
  margin: 0 0 12px;
  color: var(--accent);
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.hero h1 {
  margin: 0;
  font-size: clamp(34px, 5vw, 52px);
  line-height: 1.08;
}

.lead {
  margin: 16px 0 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 20px;
  line-height: 1.6;
}

.sublead {
  margin: 12px 0 0;
  max-width: 760px;
  color: var(--muted);
  font-size: 16px;
  line-height: 1.65;
}

.language-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 20px;
  margin-top: 8px;
}

.language-card {
  display: block;
  padding: 28px;
  border: 1px solid var(--line);
  border-radius: 28px;
  background: linear-gradient(180deg, rgba(234, 241, 255, 0.78) 0%, rgba(255, 255, 255, 1) 56%);
  box-shadow: var(--shadow);
  text-decoration: none;
}

.language-card:hover {
  border-color: #b8cae4;
}

.language-label {
  display: inline-block;
  margin-bottom: 14px;
  color: var(--accent-strong);
  font-size: 15px;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.language-card h2 {
  margin: 0;
  font-size: 34px;
  line-height: 1.1;
}

.language-card p {
  margin: 14px 0 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.6;
}

.section-title {
  margin: 40px 0 12px;
  font-size: 26px;
  line-height: 1.2;
}

.section-lead {
  margin: 0 0 20px;
  max-width: 820px;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.6;
}

.deck-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
  margin-top: 20px;
  min-width: 0;
}

.deck-card {
  display: block;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 24px;
  background: var(--panel);
  box-shadow: var(--shadow);
  text-decoration: none;
  min-width: 0;
  overflow-wrap: anywhere;
}

.deck-card:hover {
  border-color: #b8cae4;
}

.deck-tag {
  display: inline-block;
  margin-bottom: 16px;
  padding: 8px 12px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 14px;
  font-weight: 800;
}

.deck-card h2 {
  margin: 0 0 12px;
  font-size: 28px;
  line-height: 1.2;
}

.deck-card p {
  margin: 0;
  color: var(--muted);
  font-size: 18px;
  line-height: 1.55;
}

.deck-card .deck-question {
  margin-bottom: 12px;
  color: var(--ink);
  font-weight: 750;
}

.viewer {
  width: min(1440px, 100%);
  min-height: 100vh;
  margin: 0 auto;
  padding: 14px;
}

.viewer-bar {
  min-height: 44px;
  display: grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items: center;
  gap: 16px;
  margin-bottom: 12px;
  padding: 0 4px;
}

.viewer-bar a {
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.viewer-bar strong {
  overflow-wrap: anywhere;
}

.viewer > img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: contain;
  background: #fff;
  border: 1px solid var(--line);
}

.viewer-controls {
  display: flex;
  justify-content: center;
  gap: 12px;
  padding: 14px 0;
}

.viewer-controls button {
  min-width: 112px;
  min-height: 42px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: #fff;
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
}

.status-row {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: 16px 0 0;
}

.status-chip {
  display: inline-block;
  padding: 7px 10px;
  border-radius: 999px;
  font-size: 13px;
  font-weight: 800;
}

.status-chip.dual {
  background: var(--ok-soft);
  color: var(--ok);
}

.status-chip.single {
  background: var(--warn-soft);
  color: var(--warn);
}

.deck-page {
  width: min(1320px, calc(100vw - 40px));
  margin: 0 auto;
  padding: 28px 0 64px;
}

.deck-topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 24px;
}

.deck-topbar a {
  color: var(--accent);
  font-weight: 700;
  text-decoration: none;
}

.deck-topbar a:hover {
  text-decoration: underline;
}

.deck-header h1 {
  margin: 0;
  font-size: clamp(30px, 4vw, 44px);
}

.deck-header p {
  margin: 10px 0 0;
  color: var(--muted);
  font-size: 19px;
  line-height: 1.6;
}

.xrefkit-deck-navigation {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin: 24px 0;
  padding: 18px 0;
  border-top: 1px solid var(--line);
  border-bottom: 1px solid var(--line);
}

.xrefkit-deck-navigation a {
  color: var(--accent);
  font-weight: 700;
  line-height: 1.5;
  text-decoration: none;
}

.xrefkit-deck-navigation a:hover,
.xrefkit-deck-navigation a:focus-visible {
  text-decoration: underline;
}

.loop-diagram {
  display: grid;
  gap: 14px;
  margin-top: 24px;
}

.model-main,
.distribution-main {
  text-align: center;
}

.model-main .section-heading,
.model-main .improvement-note,
.distribution-main .section-heading,
.distribution-main .improvement-note {
  text-align: left;
}

.model-object,
.model-inline {
  display: block;
  width: min(640px, 100%);
  aspect-ratio: 680 / 750;
  margin: 24px auto 0;
  border: 0;
  background: transparent;
}

.model-inline svg,
.model-doc-object svg {
  display: block;
  width: 100%;
  height: 100%;
}

.distribution-object {
  display: block;
  width: min(780px, 100%);
  aspect-ratio: 680 / 500;
  margin: 24px auto 0;
  border: 0;
  background: transparent;
}

.model-reading {
  max-width: 900px;
  margin: 28px auto 0;
  padding: 24px 28px;
  border-left: 4px solid var(--accent);
  background: var(--panel);
  text-align: left;
}

.model-reading h3 {
  margin: 0 0 14px;
  font-size: 26px;
}

.model-reading p {
  margin: 0;
  color: var(--muted);
  font-size: 17px;
  line-height: 1.9;
}

.model-reading p + p {
  margin-top: 12px;
}

.model-reading a {
  color: var(--accent);
  font-weight: 750;
}

.hero-problem {
  max-width: 760px;
  margin: 18px 0 0;
  color: var(--ink);
  font-size: 18px;
  font-weight: 700;
  line-height: 1.65;
}

.hero-actions,
.tier-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.hero-actions {
  margin-top: 24px;
}

.hero-actions a,
.section-cta a,
.tier-links a {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 10px 14px;
  background: var(--panel);
  color: var(--ink);
  font-weight: 750;
  text-decoration: none;
}

.hero-actions .primary-action {
  border-color: var(--accent);
  background: var(--accent);
  color: #fff;
}

.section-cta {
  margin: 18px 0 0;
  text-align: left;
}

.learning-tiers {
  display: grid;
  gap: 14px;
  margin-top: 24px;
}

.learning-tier {
  display: grid;
  grid-template-columns: 48px 1fr;
  gap: 18px;
  border-top: 1px solid var(--line);
  padding: 22px 0 8px;
}

.learning-tier > span {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: var(--accent);
  color: #fff;
  font-weight: 800;
}

.learning-tier h3,
.learning-tier p {
  margin: 0;
}

.learning-tier p {
  margin-top: 6px;
  color: var(--muted);
}

.tier-links {
  margin-top: 14px;
}

.model-doc {
  width: min(1120px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 72px;
}

.model-doc-hero {
  padding: 44px 0 24px;
}

.model-doc-hero h1 {
  margin: 8px 0 16px;
  font-size: 48px;
}

.model-doc-hero p:last-child,
.model-doc-reading p,
.model-definitions p {
  color: var(--muted);
  font-size: 17px;
  line-height: 1.85;
}

.model-doc-object {
  display: block;
  width: min(680px, 100%);
  aspect-ratio: 680 / 750;
  margin: 12px auto 36px;
  border: 0;
}

.model-doc-reading {
  border-left: 4px solid var(--accent);
  padding: 24px 28px;
  background: var(--panel);
}

.model-doc-reading h2,
.model-definitions h2 {
  margin: 0 0 10px;
}

.model-toc {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 8px;
  margin: 28px 0;
}

.model-toc a {
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 10px 12px;
  background: var(--panel);
  color: var(--ink);
  font-weight: 700;
  text-decoration: none;
}

.model-definitions {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.model-definitions section {
  scroll-margin-top: 20px;
  border-top: 2px solid var(--line);
  padding: 20px 4px 8px;
}

.concept-doc {
  width: min(980px, calc(100% - 32px));
  margin: 0 auto;
  padding: 28px 0 80px;
}

.concept-doc-hero {
  padding: 44px 0 30px;
}

.concept-doc-hero h1 {
  max-width: 820px;
  margin: 8px 0 18px;
  font-size: clamp(36px, 4.2vw, 52px);
  line-height: 1.08;
  letter-spacing: -0.025em;
}

.concept-series {
  margin: 0;
  color: var(--accent-strong);
  font-weight: 800;
}

.concept-description {
  max-width: 820px;
  margin: 0;
  color: var(--muted);
  font-size: 20px;
  line-height: 1.65;
}

.concept-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 18px;
  margin-top: 18px;
  color: var(--muted);
  font-size: 14px;
}

.concept-body {
  max-width: 860px;
}

.concept-body h2 {
  margin: 48px 0 14px;
  font-size: clamp(28px, 3.4vw, 38px);
  line-height: 1.16;
}

.concept-body p,
.concept-body li {
  color: var(--muted);
  font-size: 17px;
  line-height: 1.85;
}

.concept-body strong {
  color: var(--ink);
}

.concept-body code {
  padding: 0.08em 0.28em;
  border-radius: 4px;
  background: #e8eef7;
  color: #173c75;
  font-size: 0.92em;
}

.concept-body ul,
.concept-body ol {
  padding-left: 1.5em;
}

.concept-table-wrap {
  width: 100%;
  margin: 24px 0;
  overflow-x: auto;
  border: 1px solid var(--line);
  background: var(--panel);
}

.concept-table {
  width: 100%;
  min-width: 680px;
  border-collapse: collapse;
}

.concept-table th,
.concept-table td {
  padding: 13px 15px;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
  line-height: 1.55;
}

.concept-table th {
  background: var(--accent-soft);
  color: var(--ink);
}

.concept-implementation {
  margin-top: 48px;
  padding: 24px 28px 26px;
  border-left: 4px solid var(--accent);
  background: var(--panel);
}

.concept-implementation h2 {
  margin-top: 0;
}

.concept-implementation table {
  margin-bottom: 18px;
}

@media (max-width: 860px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .concept-doc {
    width: calc(100vw - 24px);
    padding-top: 18px;
  }

  .concept-doc-hero {
    padding-top: 30px;
  }

  .concept-doc-hero h1 {
    font-size: 38px;
    overflow-wrap: anywhere;
  }

  .concept-body p,
  .concept-body li {
    font-size: 16px;
  }

  .concept-implementation {
    padding: 20px 18px 22px;
  }
}

@media (max-width: 720px) {
  .model-toc,
  .model-definitions {
    grid-template-columns: 1fr;
  }

  .model-doc-hero h1 {
    font-size: 38px;
  }
}

.loop-line {
  display: grid;
  grid-template-columns: repeat(6, minmax(0, 1fr));
  gap: 10px;
  align-items: stretch;
}

.loop-line.improvement {
  grid-template-columns: repeat(7, minmax(0, 1fr));
}

.loop-step {
  padding: 14px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  font-weight: 750;
  line-height: 1.35;
  text-align: center;
}

.loop-caption {
  color: var(--muted);
  font-size: 15px;
  font-weight: 700;
}

.example-flow {
  display: grid;
  gap: 10px;
  margin-top: 24px;
}

.example-step {
  padding: 16px 18px;
  border-left: 4px solid var(--accent);
  background: var(--panel);
  line-height: 1.55;
}

.slide-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 28px;
  margin-top: 28px;
}

.slide-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 26px;
  background: var(--panel);
  box-shadow: var(--shadow);
}

.slide-card img {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 18px;
  border: 1px solid #d8e1eb;
  background: #fff;
}

.slide-meta {
  margin-top: 14px;
  color: var(--muted);
  font-size: 16px;
}

@media (max-width: 860px) {
  .slide-list {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .landing {
    width: calc(100vw - 20px);
    padding: 16px 0 64px;
  }

  .hero-shell {
    padding: 18px;
    border-radius: 28px;
  }

  .hero-grid,
  .featured-rail {
    grid-template-columns: 1fr;
  }

  .operating-rationale {
    grid-template-columns: 1fr;
    gap: 18px;
  }

  .trait-grid,
  .improvement-flow,
  .entry-path-grid {
    grid-template-columns: 1fr;
  }

  .entry-path,
  .entry-path:nth-child(even) {
    padding: 20px 0;
    border-left: 0;
  }

  .mechanism-row {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .rationale-connector {
    transform: rotate(90deg);
  }

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

  .featured-steps {
    gap: 8px;
  }

  .flow-board {
    padding: 18px;
  }

  .flow-row-top,
  .flow-row-middle,
  .flow-row-bottom {
    grid-template-columns: 1fr;
  }

  .flow-row .flow-connector {
    transform: rotate(90deg);
  }

  .flow-connector {
    display: none;
  }

  .hero-copy h1 {
    font-size: 40px;
  }

  .hero-clarity-card {
    min-height: 0;
    padding: 22px;
  }

  .hero-clarity-card h2 {
    max-width: none;
  }

  .canonical-concept {
    padding: 18px;
  }

  .hero-actions {
    flex-direction: column;
  }

  .primary-button,
  .secondary-button {
    width: 100%;
  }

  .catalog-filter {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    width: 100%;
  }

  .page,
  .deck-page {
    width: calc(100vw - 24px);
  }

  .page-header {
    flex-wrap: wrap;
  }

  .hero h1,
  .lead,
  .sublead,
  .deck-card h2,
  .deck-card p {
    max-width: 100%;
    overflow-wrap: anywhere;
  }

  .deck-card h2 {
    font-size: 24px;
  }

  .language-card h2 {
    font-size: 28px;
  }

  .slide-card {
    padding: 12px;
  }

  .loop-line,
  .loop-line.improvement {
    grid-template-columns: 1fr;
  }

  .viewer {
    padding: 8px;
  }

  .viewer-bar {
    grid-template-columns: auto 1fr;
  }

  .viewer-bar strong {
    grid-column: 1 / -1;
    grid-row: 2;
  }
}