:root {
  --bg: #f6f7fa;
  --bg-accent: #edf1f6;
  --surface: rgba(255, 255, 255, 0.92);
  --surface-strong: #ffffff;
  --surface-dark: #141a22;
  --text: #18202a;
  --muted: #5f6975;
  --line: rgba(24, 32, 42, 0.1);
  --line-strong: rgba(24, 32, 42, 0.2);
  --primary: #1f4b99;
  --primary-strong: #163a79;
  --secondary: #27415f;
  --secondary-soft: #c8d7f0;
  --success: #2c7a4b;
  --danger: #bb4d36;
  --shadow: 0 18px 44px rgba(20, 28, 40, 0.08);
  --radius-xl: 30px;
  --radius-lg: 22px;
  --radius-md: 16px;
  --content-width: 1240px;
  --mono: "SFMono-Regular", "Consolas", "Menlo", monospace;
  --sans: "Avenir Next", "Hiragino Sans", "Yu Gothic", sans-serif;
  --serif: "Iowan Old Style", "Palatino Linotype", "Yu Mincho", serif;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--sans);
  color: var(--text);
  background:
    radial-gradient(circle at top left, rgba(31, 75, 153, 0.05), transparent 24%),
    radial-gradient(circle at 82% 8%, rgba(39, 65, 95, 0.05), transparent 22%),
    linear-gradient(180deg, #fafbfd 0%, #f6f7fa 42%, #edf1f6 100%);
  min-height: 100vh;
}

a {
  color: inherit;
}

.page-shell {
  width: min(calc(100% - 32px), var(--content-width));
  margin: 0 auto;
  padding: 24px 0 72px;
}

.site-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  margin-bottom: 30px;
  padding: 12px 0;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
}

.brand-mark {
  width: 46px;
  height: 46px;
  border-radius: 16px;
  display: grid;
  place-items: center;
  background: linear-gradient(135deg, var(--primary), var(--primary-strong));
  color: white;
  font-weight: 800;
  box-shadow: var(--shadow);
}

.brand-copy strong {
  display: block;
  font-size: 1rem;
  letter-spacing: 0.05em;
}

.brand-copy span {
  color: var(--muted);
  font-size: 0.9rem;
}

.nav-links {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
}

.nav-links a,
.button,
button {
  border: 1px solid transparent;
  border-radius: 999px;
  padding: 11px 17px;
  text-decoration: none;
  cursor: pointer;
  transition: transform 160ms ease, background-color 160ms ease, border-color 160ms ease, color 160ms ease;
  font: inherit;
}

.nav-links a:hover,
.button:hover,
button:hover {
  transform: translateY(-1px);
}

.button-primary,
button.button-primary {
  background: var(--primary);
  color: white;
  box-shadow: 0 10px 24px rgba(31, 75, 153, 0.18);
}

.button-secondary,
button.button-secondary,
.nav-links a {
  background: rgba(255, 255, 255, 0.78);
  border-color: var(--line);
}

.nav-links a:hover,
.button-secondary:hover,
button.button-secondary:hover {
  border-color: var(--line-strong);
}

.hero {
  display: grid;
  grid-template-columns: 1.15fr 0.85fr;
  gap: 24px;
  margin-bottom: 30px;
}

.hero.hero-single {
  grid-template-columns: 1fr;
}

.panel {
  background: var(--surface);
  border: 1px solid rgba(255, 255, 255, 0.84);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.hero-copy,
.hero-side,
.section,
.visualizer-layout > *,
.stats,
.legend,
.code-panel,
.info-card {
  padding: 24px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--primary-strong);
  font-size: 0.8rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1,
h2,
h3 {
  margin: 0 0 14px;
  line-height: 1.1;
}

h1 {
  font-family: var(--serif);
  font-size: clamp(2.2rem, 4vw, 4.2rem);
  line-height: 1.16;
  letter-spacing: -0.035em;
  overflow-wrap: anywhere;
}

h2 {
  font-size: clamp(1.5rem, 2vw, 2rem);
}

p {
  margin: 0 0 14px;
  line-height: 1.75;
  color: var(--text);
}

.hero-actions,
.pill-row,
.control-row,
.stat-grid,
.card-grid,
.topic-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
}

.pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  background: rgba(255, 255, 255, 0.64);
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text);
  font-size: 0.92rem;
}

.section {
  margin-bottom: 22px;
}

.section-heading {
  display: grid;
  grid-template-columns: minmax(0, 0.95fr) minmax(0, 1.05fr);
  gap: 18px;
  align-items: end;
  margin-bottom: 22px;
}

.section-heading-compact {
  margin-bottom: 16px;
}

.section-lead {
  margin-bottom: 18px;
  color: var(--muted);
}

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

.info-card {
  border-radius: var(--radius-lg);
  background: rgba(250, 251, 253, 0.96);
  border: 1px solid var(--line);
}

.info-card strong {
  display: block;
  margin-bottom: 8px;
  font-size: 1rem;
}

.article-block + .article-block {
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.article-block h3 {
  font-size: 1.24rem;
  margin-bottom: 10px;
}

.list-clean {
  margin: 0;
  padding-left: 18px;
  color: var(--muted);
  line-height: 1.8;
}

.visualizer-layout {
  display: grid;
  grid-template-columns: 1.45fr 0.8fr;
  gap: 20px;
}

.toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 10px;
  margin-bottom: 14px;
}

.toolbar label {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--muted);
  font-size: 0.95rem;
}

input[type="range"] {
  accent-color: var(--secondary);
}

.bars-panel {
  min-height: 360px;
}

.bars {
  height: 300px;
  display: flex;
  align-items: end;
  justify-content: stretch;
  gap: 10px;
  padding: 22px 10px 8px;
  border-radius: var(--radius-lg);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.52), rgba(255, 255, 255, 0.18)),
    repeating-linear-gradient(
      180deg,
      transparent,
      transparent 39px,
      rgba(29, 42, 45, 0.05) 39px,
      rgba(29, 42, 45, 0.05) 40px
    );
}

.bars.is-dense {
  padding-left: 4px;
  padding-right: 4px;
}

.bar-wrap {
  flex: 1 1 0;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  min-width: 0;
}

.bar {
  width: 100%;
  border-radius: 16px 16px 8px 8px;
  background: linear-gradient(180deg, #7da2ea 0%, var(--primary) 100%);
  position: relative;
  transition: height 240ms ease, background 160ms ease, transform 160ms ease;
  min-height: 18px;
}

.bar::after {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  background: linear-gradient(180deg, rgba(255,255,255,0.28), transparent 55%);
}

.bar.is-active {
  background: linear-gradient(180deg, #cfe0ff 0%, var(--secondary) 100%);
  transform: translateY(-6px);
}

.bar.is-swap {
  background: linear-gradient(180deg, #f29b8c 0%, var(--danger) 100%);
}

.bar.is-sorted {
  background: linear-gradient(180deg, #8fd4ac 0%, var(--success) 100%);
}

.bar.is-found {
  background: linear-gradient(180deg, #f6e59b 0%, #d9a404 100%);
  transform: translateY(-6px);
}

.bar.is-candidate,
.cell.is-candidate,
.graph-node.is-candidate circle,
.grid-cell.is-candidate {
  background: linear-gradient(180deg, #f3b3a5 0%, var(--danger) 100%);
}

.bar.is-dim {
  opacity: 0.28;
}

.bar.is-mid {
  box-shadow: 0 0 0 4px rgba(209, 124, 56, 0.22);
}

.bar-value {
  font-weight: 700;
  color: var(--text);
  font-size: 0.78rem;
  line-height: 1;
}

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 12px;
}

.stat {
  padding: 16px;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.68);
  border: 1px solid var(--line);
}

.stat span {
  display: block;
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 6px;
}

.stat strong {
  font-size: 1.6rem;
}

.legend {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.legend-item {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--muted);
  font-size: 0.92rem;
}

.legend-swatch {
  width: 14px;
  height: 14px;
  border-radius: 999px;
}

.legend-swatch.is-active {
  background: var(--secondary);
}

.legend-swatch.is-swap {
  background: var(--danger);
}

.legend-swatch.is-sorted {
  background: var(--success);
}

.legend-swatch.is-found,
.legend-swatch.is-chosen {
  background: #d9a404;
}

.legend-swatch.is-dim {
  background: rgba(29, 42, 45, 0.2);
}

.legend-swatch.is-frontier {
  background: #4e7fd1;
}

.legend-swatch.is-visited {
  background: #5f8186;
}

.code-panel pre {
  margin: 0;
  padding: 18px;
  overflow: auto;
  border-radius: var(--radius-lg);
  background: #1f2527;
  color: #dce7e9;
  font-family: var(--mono);
  line-height: 1.75;
}

.code-line {
  display: block;
  padding: 0 10px;
  margin: 0 -10px;
  border-radius: 10px;
  transition: background-color 160ms ease, color 160ms ease;
}

.code-line.active {
  background: rgba(209, 124, 56, 0.28);
  color: #fff3d9;
}

.status-note {
  color: var(--primary-strong);
  font-weight: 700;
  margin-top: 12px;
}

.table-lite {
  width: 100%;
  border-collapse: collapse;
}

.table-lite th,
.table-lite td {
  padding: 14px 12px;
  text-align: left;
  border-bottom: 1px solid var(--line);
  color: var(--muted);
}

.table-lite th {
  color: var(--text);
}

.mini-chart {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
  align-items: end;
  min-height: 190px;
  padding-top: 16px;
}

.mini-column {
  text-align: center;
}

.mini-column .shape {
  width: 100%;
  border-radius: 18px 18px 8px 8px;
  background: linear-gradient(180deg, rgba(209, 124, 56, 0.95), rgba(31, 111, 120, 0.95));
}

.mini-column span {
  display: block;
  margin-top: 10px;
  color: var(--muted);
}

.footer {
  margin-top: 34px;
  padding: 20px 0 0;
  color: var(--muted);
  font-size: 0.92rem;
}

.hero-editorial {
  align-items: stretch;
}

.hero-copy-wide {
  min-height: 0;
}

.hero-split {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(280px, 0.7fr);
  gap: 24px;
  align-items: start;
}

.hero-stack {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}

.hero-kicker {
  margin-bottom: 12px;
  color: var(--muted);
  font-size: 0.92rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
}

.hero-note {
  max-width: 72rem;
  padding: 6px 0 0;
  font-size: 1.03rem;
}

.hero-copy-wide h1 {
  margin-bottom: 18px;
}

.hero-copy-wide > .hero-actions {
  margin-top: 18px;
}

.hero-ribbon {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 34px;
  padding-top: 20px;
  border-top: 1px solid var(--line);
}

.hero-ribbon span {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(247, 249, 252, 0.94);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.hero-ribbon-compact {
  margin-top: 18px;
  padding-top: 0;
  border-top: 0;
}

.hero-inline-block {
  margin-top: 26px;
  padding-top: 26px;
  border-top: 1px solid var(--line);
}

.data-panel {
  background:
    radial-gradient(circle at top right, rgba(31, 75, 153, 0.08), transparent 34%),
    linear-gradient(180deg, rgba(252, 253, 255, 0.96), rgba(243, 246, 250, 0.92));
}

.metric-stack,
.ladder-list {
  display: grid;
  gap: 14px;
}

.metric-stack-inline,
.ladder-list-inline {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.metric-card,
.ladder-step {
  padding: 18px;
  border-radius: var(--radius-lg);
  background: rgba(251, 252, 254, 0.96);
  border: 1px solid var(--line);
}

.metric-card {
  min-height: 160px;
  background: rgba(255, 255, 255, 0.84);
}

.metric-value {
  display: inline-block;
  margin-bottom: 10px;
  color: var(--primary);
  font-size: 0.88rem;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.metric-card strong,
.ladder-step strong {
  display: block;
  margin-bottom: 8px;
  font-size: 1.05rem;
}

.ladder-step-hot {
  background: linear-gradient(180deg, rgba(231, 239, 255, 0.96), rgba(251, 252, 254, 0.96));
  border-color: rgba(31, 75, 153, 0.14);
}

.section-accent {
  background:
    linear-gradient(180deg, rgba(248, 250, 253, 0.96), rgba(241, 245, 249, 0.92));
}

.feature-grid,
.path-grid,
.catalog-grid,
.pattern-grid,
.reading-grid,
.warning-grid,
.sequence-grid {
  display: grid;
  gap: 18px;
}

.feature-grid,
.path-grid,
.pattern-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.feature-card,
.path-card,
.pattern-card,
.reading-card,
.warning-card,
.catalog-column,
.sequence-card {
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
}

.feature-card,
.reading-card,
.warning-card {
  padding: 22px;
  background: rgba(251, 252, 254, 0.96);
}

.feature-index {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 34px;
  height: 34px;
  margin-bottom: 14px;
  border-radius: 999px;
  background: var(--text);
  color: white;
  font-size: 0.85rem;
  font-weight: 800;
}

.feature-card strong,
.path-card h3,
.catalog-column h3,
.pattern-head strong,
.reading-card strong,
.warning-card strong,
.sequence-card strong {
  display: block;
  margin-bottom: 10px;
}

.path-card,
.catalog-column,
.pattern-card,
.sequence-card {
  padding: 24px;
  background: rgba(251, 252, 254, 0.96);
}

.path-card-primary {
  background:
    linear-gradient(135deg, rgba(22, 58, 121, 0.98), rgba(31, 75, 153, 0.94));
  border-color: rgba(255, 255, 255, 0.18);
  color: white;
}

.path-card-primary p,
.path-card-primary .path-label,
.path-card-primary .path-links a {
  color: rgba(255, 255, 255, 0.88);
}

.path-label,
.catalog-label {
  margin: 0 0 10px;
  color: var(--primary);
  font-size: 0.82rem;
  font-weight: 800;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.path-card h3 {
  font-size: 1.28rem;
}

.path-links,
.path-tags {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.path-links a {
  display: inline-flex;
  align-items: center;
  min-height: 40px;
  padding: 8px 14px;
  border-radius: 999px;
  background: rgba(255, 255, 255, 0.14);
  border: 1px solid rgba(255, 255, 255, 0.22);
  text-decoration: none;
}

.catalog-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.catalog-column {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.catalog-link {
  display: block;
  padding: 16px 0;
  border-top: 1px solid var(--line);
  text-decoration: none;
}

.catalog-link:first-of-type {
  padding-top: 4px;
  border-top: 0;
}

.catalog-link strong {
  display: block;
  margin-bottom: 4px;
  font-size: 1rem;
}

.catalog-link span {
  color: var(--muted);
  font-size: 0.94rem;
}

.section-dark {
  background:
    radial-gradient(circle at top right, rgba(212, 126, 56, 0.18), transparent 28%),
    linear-gradient(180deg, #162127 0%, #11181c 100%);
  color: #f4efe6;
  border-color: rgba(255, 255, 255, 0.08);
}

.section-dark .eyebrow,
.section-dark .section-lead,
.section-dark p,
.section-dark .sequence-card p {
  color: rgba(244, 239, 230, 0.78);
}

.top-hero,
.top-guide-section,
.top-catalog-section {
  padding: 28px;
}

.top-hero {
  margin-bottom: 22px;
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.98), rgba(248, 250, 253, 0.94));
}

.top-hero-head {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  gap: 12px 18px;
  margin-bottom: 10px;
}

.top-hero-subtitle {
  margin: 0;
  color: var(--muted);
  letter-spacing: 0.08em;
  font-size: 0.94rem;
}

.top-hero h1 {
  max-width: none;
  margin-bottom: 22px;
  font-size: clamp(2.1rem, 3.7vw, 3.5rem);
  line-height: 1.08;
}

.title-line {
  display: block;
}

.title-line-nowrap {
  white-space: nowrap;
}

.top-lead {
  max-width: 58rem;
  font-size: 1.14rem;
  line-height: 1.95;
  color: rgba(23, 33, 38, 0.88);
}

.top-hero-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 20px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.top-hero-meta span {
  display: inline-flex;
  align-items: center;
  min-height: 36px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(247, 249, 252, 0.94);
  border: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.9rem;
}

.study-map {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 14px;
}

.study-step {
  display: block;
  min-height: 164px;
  padding: 20px;
  border-radius: var(--radius-lg);
  border: 1px solid var(--line);
  background: rgba(250, 251, 253, 0.98);
  text-decoration: none;
}

.study-step span {
  display: inline-block;
  margin-bottom: 14px;
  color: var(--primary);
  font-size: 0.88rem;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.study-step strong {
  display: block;
  margin-bottom: 10px;
  font-size: 1.08rem;
}

.study-step p {
  margin-bottom: 0;
  color: var(--muted);
}

.catalog-list {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0 24px;
}

.catalog-item {
  display: block;
  padding: 18px 0;
  border-top: 1px solid var(--line);
  text-decoration: none;
}

.catalog-item strong {
  display: block;
  margin-bottom: 6px;
  font-size: 1.05rem;
}

.catalog-item p {
  margin-bottom: 0;
  color: var(--muted);
}

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

.sequence-card {
  display: block;
  min-height: 180px;
  text-decoration: none;
  color: inherit;
  background: rgba(255, 255, 255, 0.06);
  border-color: rgba(255, 255, 255, 0.12);
}

.sequence-card span {
  display: inline-block;
  margin-bottom: 18px;
  color: var(--secondary-soft);
  font-size: 0.9rem;
  font-weight: 800;
  letter-spacing: 0.14em;
}

.pattern-head {
  margin-bottom: 12px;
}

.pattern-badge {
  display: inline-flex;
  align-items: center;
  min-height: 34px;
  margin-bottom: 12px;
  padding: 6px 12px;
  border-radius: 999px;
  background: rgba(31, 75, 153, 0.12);
  color: var(--primary-strong);
  font-size: 0.85rem;
  font-weight: 800;
}

.pattern-card-hot .pattern-badge {
  background: rgba(187, 77, 54, 0.12);
  color: var(--danger);
}

.pattern-scale {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  align-items: end;
  min-height: 140px;
  margin-top: 20px;
}

.pattern-scale span {
  display: block;
  border-radius: 18px 18px 8px 8px;
  background: linear-gradient(180deg, rgba(125, 162, 234, 0.6), var(--primary));
}

.pattern-card-hot .pattern-scale span {
  background: linear-gradient(180deg, rgba(207, 224, 255, 0.8), var(--secondary));
}

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

.warning-grid {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.warning-card {
  background: linear-gradient(180deg, rgba(247, 250, 255, 0.96), rgba(239, 244, 250, 0.92));
}

.toc-section {
  background: linear-gradient(180deg, rgba(249, 251, 254, 0.96), rgba(242, 246, 250, 0.92));
}

.toc-links {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
}

.toc-links a {
  display: inline-flex;
  align-items: center;
  min-height: 42px;
  padding: 10px 14px;
  border-radius: 999px;
  background: rgba(249, 251, 254, 0.96);
  border: 1px solid var(--line);
  text-decoration: none;
  color: var(--text);
}

.toc-links a:hover {
  transform: translateY(-1px);
}

.visual-stage {
  border-radius: var(--radius-lg);
  background:
    linear-gradient(180deg, rgba(255, 255, 255, 0.52), rgba(255, 255, 255, 0.18)),
    repeating-linear-gradient(
      180deg,
      transparent,
      transparent 39px,
      rgba(29, 42, 45, 0.05) 39px,
      rgba(29, 42, 45, 0.05) 40px
    );
  min-height: 320px;
  padding: 18px;
}

.visual-caption {
  margin: 14px 0 0;
  color: var(--primary-strong);
  font-weight: 700;
}

.cell-row {
  min-height: 240px;
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(54px, 1fr));
  gap: 10px;
  align-items: center;
}

.cell {
  min-height: 84px;
  border-radius: 18px;
  padding: 12px 8px;
  background: linear-gradient(180deg, #7da2ea 0%, var(--primary) 100%);
  color: white;
  display: grid;
  place-items: center;
  text-align: center;
  border: 1px solid rgba(255, 255, 255, 0.18);
  transition: transform 160ms ease, opacity 160ms ease;
}

.cell.is-active,
.grid-cell.is-active {
  background: linear-gradient(180deg, #cfe0ff 0%, var(--secondary) 100%);
  color: white;
  transform: translateY(-4px);
}

.cell.is-swap,
.grid-cell.is-swap {
  background: linear-gradient(180deg, #f29b8c 0%, var(--danger) 100%);
}

.cell.is-sorted,
.grid-cell.is-sorted {
  background: linear-gradient(180deg, #8fd4ac 0%, var(--success) 100%);
}

.cell.is-found,
.grid-cell.is-found {
  background: linear-gradient(180deg, #f6e59b 0%, #d9a404 100%);
  color: #3b2d03;
}

.cell.is-dim,
.graph-node.is-dim,
.edge-line.is-dim,
.grid-cell.is-dim {
  opacity: 0.28;
}

.cell.is-frontier,
.graph-node.is-frontier circle,
.grid-cell.is-frontier {
  background: linear-gradient(180deg, #a9c9f6 0%, #4e7fd1 100%);
}

.cell.is-visited,
.graph-node.is-visited circle,
.grid-cell.is-visited {
  background: linear-gradient(180deg, #b9d5d8 0%, #5f8186 100%);
}

.cell.is-chosen,
.graph-node.is-chosen circle,
.edge-line.is-chosen,
.grid-cell.is-chosen {
  background: linear-gradient(180deg, #f6e59b 0%, #d9a404 100%);
}

.cell-main {
  display: block;
  font-weight: 800;
}

.cell-sub {
  display: block;
  margin-top: 6px;
  font-size: 0.78rem;
  opacity: 0.9;
}

.graph-scene {
  min-height: 260px;
}

.graph-scene svg {
  width: 100%;
  height: auto;
}

.edge-line {
  stroke: rgba(29, 42, 45, 0.22);
  stroke-width: 4;
}

.edge-line.is-active,
.edge-line.is-path {
  stroke: var(--secondary);
}

.edge-line.is-chosen {
  stroke: #d9a404;
}

.graph-node circle {
  fill: white;
  stroke: rgba(29, 42, 45, 0.22);
  stroke-width: 3;
}

.graph-node text,
.edge-label {
  fill: var(--text);
  font-size: 14px;
  font-weight: 700;
  text-anchor: middle;
}

.graph-node.is-active circle,
.graph-node.is-mid circle,
.grid-cell.is-mid {
  fill: #ffd48c;
  stroke: var(--secondary);
}

.graph-node.is-found circle {
  fill: #f6e59b;
  stroke: #d9a404;
}

.graph-node.is-path circle {
  fill: #e7d2ff;
  stroke: #7154b8;
}

.grid-scene {
  overflow: auto;
}

.grid-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 8px;
}

.grid-cell {
  min-width: 54px;
  height: 54px;
  text-align: center;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.76);
  border: 1px solid var(--line);
  color: var(--text);
  font-weight: 700;
}

.tower-scene {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  align-items: end;
  min-height: 260px;
}

.rod {
  position: relative;
  min-height: 240px;
  display: flex;
  justify-content: center;
  align-items: end;
}

.rod::before {
  content: "";
  position: absolute;
  bottom: 22px;
  width: 10px;
  height: 170px;
  border-radius: 999px;
  background: rgba(29, 42, 45, 0.16);
}

.rod-stack {
  position: relative;
  z-index: 1;
  width: 100%;
  display: flex;
  flex-direction: column-reverse;
  align-items: center;
  gap: 8px;
  padding-bottom: 30px;
}

.rod-base {
  position: absolute;
  bottom: 12px;
  width: 85%;
  height: 12px;
  border-radius: 999px;
  background: rgba(29, 42, 45, 0.2);
}

.disc {
  height: 24px;
  border-radius: 999px;
  background: linear-gradient(180deg, #ffd48c 0%, var(--secondary) 100%);
  color: #342411;
  font-weight: 800;
  display: grid;
  place-items: center;
}

.mini-card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 12px;
}

.mini-info-card {
  padding: 14px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.72);
  border: 1px solid var(--line);
}

.mini-info-card strong {
  display: block;
  margin-bottom: 8px;
}

@media (max-width: 960px) {
  .hero,
  .visualizer-layout,
  .card-grid,
  .topic-grid,
  .feature-grid,
  .path-grid,
  .catalog-grid,
  .catalog-list,
  .pattern-grid,
  .reading-grid,
  .warning-grid,
  .sequence-grid,
  .metric-stack-inline,
  .ladder-list-inline,
  .study-map {
    grid-template-columns: 1fr;
  }

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

  .section-heading,
  .hero-split,
  .hero-stack {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .page-shell {
    width: min(calc(100% - 20px), var(--content-width));
    padding-top: 16px;
  }

  .hero-copy,
  .hero-side,
  .section,
  .visualizer-layout > *,
  .stats,
  .legend,
  .code-panel,
  .info-card,
  .feature-card,
  .path-card,
  .catalog-column,
  .pattern-card,
  .reading-card,
  .warning-card,
  .sequence-card,
  .top-hero,
  .top-guide-section,
  .top-catalog-section {
    padding: 18px;
  }

  .bars {
    gap: 6px;
  }

  .toolbar {
    align-items: stretch;
  }

  .toolbar label {
    width: 100%;
    justify-content: space-between;
  }

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

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