:root {
  --bg: #f5f6f7;
  --surface: #ffffff;
  --surface-soft: #fafbfc;
  --text: #1f2933;
  --muted: #5f6b76;
  --line: #d9dee4;
  --accent: #35566e;
  --accent-soft: #eef3f6;
  --radius-lg: 10px;
  --radius-md: 8px;
  --radius-sm: 6px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

a {
  color: inherit;
}

code {
  font-family: "SFMono-Regular", Consolas, monospace;
}

.site-header,
.page-shell {
  position: relative;
  z-index: 1;
}

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1.2rem;
  border-bottom: 1px solid var(--line);
  background: var(--surface);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.9rem;
  text-decoration: none;
}

.brand-mark {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 2.9rem;
  height: 1.95rem;
  padding: 0 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--surface);
  color: var(--text);
  font-size: 0.83rem;
  font-weight: 600;
  letter-spacing: 0.04em;
}

.brand-copy {
  display: grid;
  gap: 0.05rem;
}

.brand-copy strong {
  font-size: 0.98rem;
}

.brand-copy small {
  color: var(--muted);
}

.site-nav {
  display: inline-flex;
  gap: 0.35rem;
  padding: 0.18rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-md);
  background: var(--surface);
}

.site-nav a {
  padding: 0.42rem 0.72rem;
  border-radius: var(--radius-sm);
  color: var(--muted);
  text-decoration: none;
}

.site-nav a.is-active {
  background: var(--accent-soft);
  color: var(--text);
  box-shadow: inset 0 0 0 1px var(--line);
}

.page-shell {
  width: min(1120px, calc(100vw - 1.4rem));
  margin: 0 auto;
  padding: 0.9rem 0 1.6rem;
}

.hero {
  display: grid;
  grid-template-columns: minmax(0, 1fr) minmax(280px, 360px);
  gap: 0.9rem;
  align-items: start;
}

.hero-copy,
.hero-card,
.panel {
  border: 1px solid var(--line);
  background: var(--surface);
}

.hero-copy,
.hero-card {
  border-radius: var(--radius-lg);
  padding: 0.95rem 1rem;
}

.hero-copy h1,
.panel h2,
.markdown-article h1,
.markdown-article h2,
.markdown-article h3 {
  margin: 0;
  line-height: 1.15;
  font-weight: 600;
}

.hero-copy h1 {
  font-size: clamp(1.32rem, 2vw, 1.72rem);
}

.hero-decoder h1 {
  white-space: nowrap;
}

.hero-text {
  margin: 0.62rem 0 0;
  color: var(--muted);
  font-size: 0.95rem;
  line-height: 1.5;
}

.hero-text code,
.status-panel code {
  padding: 0.1rem 0.28rem;
  border-radius: 0.28rem;
  background: var(--accent-soft);
}

.eyebrow {
  margin: 0 0 0.36rem;
  color: var(--accent);
  font-size: 0.74rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0.65rem;
  margin-top: 0.75rem;
}

.bundle-summary {
  display: grid;
  gap: 0.25rem;
  margin-top: 0.75rem;
}

.bundle-stat-row {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: baseline;
}

.bundle-stat-label {
  color: var(--muted);
  font-size: 0.84rem;
}

.bundle-stat-value {
  line-height: 1.45;
}

.summary-card {
  padding: 0.7rem 0.78rem;
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--line);
}

.summary-card > .summary-label,
.meta-pair > .meta-label,
.example-strip > span,
.toc-list a {
  display: block;
  color: var(--muted);
  font-size: 0.84rem;
}

.summary-value {
  margin-top: 0.25rem;
  line-height: 1.35;
  font-weight: 600;
}

.summary-value .katex-display,
.formula-intro .katex-display,
.math-block-wrap .katex-display {
  margin: 0.15rem 0;
  overflow-x: auto;
  overflow-y: hidden;
}

.decoder-form {
  display: grid;
  gap: 0.55rem;
}

.field-label {
  font-size: 0.92rem;
  font-weight: 600;
}

.input-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.55rem;
}

input,
button {
  font: inherit;
}

input {
  width: 100%;
  padding: 0.7rem 0.78rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
}

input:focus {
  outline: 2px solid #dfe7ef;
  border-color: var(--accent);
}

button {
  padding: 0.7rem 0.88rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface);
  color: var(--text);
  font-weight: 600;
  cursor: pointer;
}

button:hover {
  background: var(--accent-soft);
}

.example-strip {
  margin-top: 0.85rem;
  padding-top: 0.85rem;
  border-top: 1px solid var(--line);
}

.example-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  margin-top: 0.45rem;
}

.example-buttons button {
  display: grid;
  gap: 0.08rem;
  padding: 0.46rem 0.62rem;
  text-align: left;
}

.example-label {
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.83rem;
}

.example-caption {
  color: var(--muted);
  font-size: 0.78rem;
}

.status-panel {
  margin-top: 0.85rem;
  padding: 0.78rem 0.88rem;
  border-radius: var(--radius-md);
  background: var(--surface);
  border: 1px solid var(--line);
  color: var(--text);
  line-height: 1.45;
}

.status-panel.is-error {
  background: #fff7f7;
  border-color: #e4c9c9;
  color: #7b3d3d;
}

.status-panel.is-success {
  background: #f7fafc;
  border-color: #d5dfe8;
}

.result-grid {
  display: grid;
  gap: 0.9rem;
  margin-top: 0.9rem;
}

.panel {
  border-radius: var(--radius-lg);
  padding: 0.95rem 1rem;
}

.panel-heading {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: end;
}

.panel-heading h2 {
  font-size: 1.08rem;
}

.factor-grid,
.summand-grid {
  display: grid;
  gap: 0.75rem;
  margin-top: 0.8rem;
}

.factor-grid {
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
}

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

.factor-card,
.summand-card,
.formula-card,
.toc-list a {
  border-radius: var(--radius-md);
  border: 1px solid var(--line);
  background: var(--surface);
}

.factor-card,
.summand-card,
.formula-card {
  padding: 0.8rem;
}

.factor-card header,
.summand-card header {
  display: flex;
  justify-content: space-between;
  gap: 0.8rem;
  align-items: baseline;
}

.factor-card h3,
.summand-card h3 {
  margin: 0.08rem 0 0;
  font-size: 0.98rem;
}

.factor-index {
  color: var(--muted);
  font-size: 0.92rem;
  margin: 0;
}

.factor-description {
  margin-left: auto;
  text-align: right;
}

.factor-description-link {
  color: inherit;
  text-decoration: none;
}

.factor-description-link:hover {
  text-decoration: underline;
}

.factor-metric-line {
  display: flex;
  gap: 0.35rem;
  align-items: baseline;
  margin: 0.35rem 0 0;
  font-size: 0.88rem;
}

.factor-metric-line strong {
  font-weight: 600;
}

.pill {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.45rem;
  border-radius: var(--radius-sm);
  background: var(--accent-soft);
  border: 1px solid var(--line);
  color: var(--text);
  font-size: 0.8rem;
  font-weight: 600;
}

.math-pill .katex {
  font-size: 0.95em;
}

.factor-title-link,
.weight-row-link,
.formula-factor-link {
  color: inherit;
  text-decoration: none;
}

.factor-title-link:hover,
.weight-row-link:hover,
.formula-factor-link:hover {
  text-decoration: underline;
}

.meta-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(120px, 1fr));
  gap: 0.55rem;
  margin-top: 0.75rem;
}

.meta-pair strong {
  display: block;
  margin-top: 0.2rem;
  line-height: 1.35;
}

.diagram-panel {
  display: flex;
  align-items: center;
  justify-content: flex-start;
  margin-top: 0.75rem;
  padding: 0;
  border: 0;
  border-radius: 0;
  background: transparent;
  overflow-x: auto;
}

.dynkin {
  display: block;
  flex: 0 1 auto;
  width: auto;
  max-width: 100%;
  height: auto;
}

.dynkin-body {
  stroke-width: 1;
  stroke-linejoin: bevel;
  stroke-linecap: butt;
  stroke: #111;
  fill: #fff;
}

.dynkin circle.active {
  fill: #000;
  stroke: #000;
}

.dynkin-weight {
  fill: var(--text);
  font-size: 6px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  stroke: none;
}

.factor-note,
.summand-note,
.formula-note {
  margin: 0.7rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
  line-height: 1.45;
}

.canonical-summary {
  margin-top: 0.75rem;
}

.formula-intro {
  margin-bottom: 0.25rem;
}

.formula-grid {
  display: grid;
  gap: 0.6rem;
}

.formula-row {
  padding: 0.65rem 0.72rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
}

.formula-factor {
  font-weight: 600;
}

.formula-values {
  display: grid;
  gap: 0.22rem;
  margin-top: 0.35rem;
}

.formula-line,
.weight-line {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: baseline;
}

.formula-term,
.weight-term {
  min-width: 7.2rem;
  font-size: 0.88rem;
  font-weight: 600;
}

.formula-value,
.weight-value {
  min-width: 0;
}

.summand-factor {
  color: var(--muted);
}

.summand-factor-rank {
  color: var(--muted);
  font-size: 0.84rem;
}

.summand-lines {
  display: grid;
  gap: 0.28rem;
  margin-top: 0.35rem;
}

.summand-line {
  display: flex;
  flex-wrap: wrap;
  gap: 0.45rem;
  align-items: baseline;
  line-height: 1.45;
}

.summand-assignment,
.class-assignment {
  display: inline-flex;
  flex-wrap: wrap;
  gap: 0.22rem;
  align-items: baseline;
}

.summary-value .bundle-description {
  line-height: 1.45;
}

.formula-title {
  margin-top: 0.15rem;
}

.formula-note.is-fano strong {
  color: #20543c;
}

.formula-note.is-cy strong {
  color: #35566e;
}

.weight-list {
  display: grid;
  gap: 0.55rem;
  margin-top: 0.75rem;
}

.weight-row {
  padding: 0.65rem 0.72rem;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  background: var(--surface-soft);
}

.weight-row-head {
  display: flex;
  justify-content: space-between;
  gap: 0.8rem;
  align-items: baseline;
}

.weight-row-title {
  display: block;
  font-size: 0.95rem;
}

.weight-row-subtle,
.weight-rank {
  color: var(--muted);
  font-size: 0.84rem;
}

.weight-row-body {
  display: grid;
  gap: 0.18rem;
  margin-top: 0.35rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.specification-shell {
  display: grid;
  gap: 0.8rem;
}

.hero-specification {
  grid-template-columns: 1fr;
  align-items: stretch;
}

.toc-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(170px, 1fr));
  gap: 0.4rem;
}

.toc-list a {
  height: 100%;
  padding: 0.48rem 0.62rem;
  text-decoration: none;
}

.markdown-article {
  margin-top: 0.25rem;
}

.markdown-article > * {
  margin-top: 0.45rem;
  margin-bottom: 0.45rem;
}

.markdown-article > :first-child {
  margin-top: 0;
}

.markdown-article > :last-child {
  margin-bottom: 0;
}

.markdown-article h1 {
  font-size: 1.38rem;
}

.markdown-article h2 {
  margin-top: 0.8rem;
  font-size: 1.08rem;
}

.markdown-article h3 {
  margin-top: 0.55rem;
  font-size: 0.98rem;
}

.markdown-article p {
  margin: 0.42rem 0;
}

.markdown-article p,
.markdown-article li,
.markdown-article td,
.markdown-article th {
  line-height: 1.45;
}

.markdown-article ul,
.markdown-article ol {
  margin: 0.18rem 0 0.28rem;
  padding-left: 1.2rem;
}

.markdown-article pre {
  overflow-x: auto;
  margin: 0.1rem 0;
  padding: 0.72rem 0.84rem;
  border-radius: var(--radius-md);
  background: #f0f3f6;
  color: var(--text);
  border: 1px solid var(--line);
  font-size: 0.9rem;
}

.markdown-article code {
  padding: 0.08rem 0.28rem;
  border-radius: 0.28rem;
  background: var(--accent-soft);
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 0.92em;
}

.markdown-article pre code {
  padding: 0;
  background: transparent;
}

.markdown-article a {
  color: var(--accent);
}

.example-link {
  text-decoration: none;
}

.example-link:hover code {
  background: #dfe7ef;
}

.markdown-article table {
  width: 100%;
  border-collapse: collapse;
  margin: 0.15rem 0;
  font-size: 0.92rem;
}

.markdown-article th,
.markdown-article td {
  padding: 0.44rem 0.54rem;
  border: 1px solid var(--line);
  text-align: left;
  vertical-align: top;
}

.markdown-article th {
  background: var(--accent-soft);
}

.math-block-wrap {
  overflow-x: auto;
  overflow-y: hidden;
}

.summary-value .katex,
.meta-pair strong .katex,
.weight-row-subtle .katex,
.formula-line .katex,
.math-pill .katex,
.factor-title-link .katex,
.formula-factor-link .katex,
.weight-row-title .katex,
.factor-description-link .katex,
.summand-factor .katex,
.summand-assignment .katex {
  display: inline-flex;
  align-items: baseline;
  max-width: 100%;
  white-space: nowrap;
}

@media (max-width: 960px) {
  .site-header {
    flex-direction: column;
    align-items: start;
  }

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

  .page-shell {
    width: min(100vw - 1rem, 1120px);
  }

  .input-row {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 720px) {
  .hero-decoder h1 {
    white-space: normal;
  }

  .panel-heading,
  .factor-card header,
  .summand-card header,
  .weight-row-head {
    flex-direction: column;
    gap: 0.15rem;
    align-items: start;
  }

  .factor-description {
    margin-left: 0;
    text-align: left;
  }

  .formula-term,
  .weight-term {
    min-width: 0;
  }
}

@media (max-width: 640px) {
  .site-header {
    padding: 0.85rem 0.85rem;
  }

  .page-shell {
    width: calc(100vw - 0.8rem);
    padding-bottom: 2rem;
  }

  .hero-copy,
  .hero-card,
  .panel {
    padding: 0.9rem;
  }

  .hero-copy h1 {
    font-size: 1.35rem;
  }

  .site-nav {
    width: 100%;
    justify-content: space-between;
  }

  .site-nav a {
    flex: 1 1 0;
    text-align: center;
  }
}