:root {
  color-scheme: light dark;
  --ink: #2d3036;
  --muted: #6d665f;
  --paper: #f3f2ef;
  --surface: rgba(255, 255, 255, 0.9);
  --surface-solid: #ffffff;
  --line: #ddd6cf;
  --accent: hsl(28, 90%, 55%);
  --accent-strong: hsl(25, 84%, 36%);
  --accent-soft: hsl(28, 90%, 94%);
  --definition: hsl(210, 72%, 43%);
  --definition-soft: hsl(210, 78%, 94%);
  --eyebrow: hsl(25, 78%, 39%);
  --shadow: 0 20px 55px rgba(88, 55, 30, 0.12);
  background: var(--paper);
  color: var(--ink);
  font-family:
    Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  font-synthesis: none;
  line-height: 1.65;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 8% 8%, hsla(28, 90%, 55%, 0.14), transparent 27rem),
    radial-gradient(circle at 92% 24%, hsla(42, 88%, 58%, 0.09), transparent 24rem),
    var(--paper);
}

a { color: var(--accent-strong); text-underline-offset: 0.18em; }
a:hover { color: var(--accent); }
a:focus-visible {
  outline: 3px solid hsla(28, 90%, 55%, 0.38);
  outline-offset: 3px;
  border-radius: 0.25rem;
}

.site-header {
  position: sticky;
  z-index: 10;
  top: 0;
  border-top: 3px solid var(--accent);
  border-bottom: 1px solid rgba(221, 214, 207, 0.9);
  background: rgba(247, 245, 242, 0.86);
  backdrop-filter: blur(18px);
}
.site-header nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: min(100% - 2rem, 72rem);
  min-height: 4.5rem;
  margin: 0 auto;
  gap: 1.5rem;
}
.site-header a { color: inherit; text-decoration: none; }
.brand { display: inline-flex; align-items: center; gap: 0.75rem; }
.brand-mark {
  display: grid;
  width: 2.35rem;
  height: 2.35rem;
  place-items: center;
  border-radius: 0.75rem;
  background: linear-gradient(145deg, var(--accent), #f2a13c);
  box-shadow: 0 8px 20px hsla(28, 90%, 40%, 0.24);
  color: white;
  font-size: 0.72rem;
  font-weight: 800;
  letter-spacing: -0.04em;
}
.brand-copy { display: grid; line-height: 1.15; }
.brand-copy strong { font-size: 0.98rem; letter-spacing: -0.02em; }
.brand-copy small { margin-top: 0.2rem; color: var(--muted); font-size: 0.72rem; }
.nav-links { display: flex; align-items: center; gap: 0.35rem; }
.nav-links a {
  padding: 0.55rem 0.8rem;
  border-radius: 0.65rem;
  color: var(--muted);
  font-size: 0.88rem;
  font-weight: 650;
}
.nav-links a:hover { background: var(--accent-soft); color: var(--accent-strong); }

main { width: min(100% - 2rem, 52rem); margin: clamp(2.5rem, 7vw, 5.5rem) auto; }
.catalog-home { width: min(100% - 2rem, 72rem); }
.hero { max-width: 55rem; padding: 1rem 0 clamp(1.5rem, 4vw, 3rem); }
.hero::before {
  display: block;
  width: 4.5rem;
  height: 0.32rem;
  margin-bottom: 1.4rem;
  border-radius: 999px;
  background: linear-gradient(90deg, var(--accent), #f2b04e);
  content: "";
}
.eyebrow, .section-kicker {
  margin: 0 0 0.75rem;
  color: var(--eyebrow);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-transform: uppercase;
}
h1, h2, h3 {
  margin-top: 0;
  color: var(--ink);
  font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif;
  line-height: 1.12;
  letter-spacing: -0.025em;
}
h1 { margin-bottom: 1.25rem; font-size: clamp(2.2rem, 6vw, 4rem); }
.catalog-page h1, .section-page h1 { font-size: clamp(2.1rem, 5vw, 3.4rem); }
h2 { margin-top: 2.5rem; font-size: clamp(1.5rem, 3vw, 2rem); }
.prose h2 { color: var(--accent-strong); }
h3 { font-size: 1.25rem; }
.lede, .prose > h1 + p {
  max-width: 44rem;
  color: var(--muted);
  font-size: clamp(1.08rem, 2vw, 1.28rem);
  line-height: 1.7;
}
.prose { font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif; font-size: 1.06rem; }
.prose p, .prose li { max-width: 46rem; }

.catalog-index, .section-index, .declarations { margin: 0; padding: 0; list-style: none; }
.catalog-groups { display: grid; gap: clamp(2.5rem, 6vw, 4.5rem); }
.catalog-group { scroll-margin-top: 6rem; }
.catalog-group h2 {
  margin: 0 0 1rem;
  font-size: clamp(1.55rem, 3vw, 2rem);
}
.catalog-group h2 span {
  color: var(--definition);
  font-family: ui-sans-serif, system-ui, sans-serif;
}
.catalog-group#theorems h2 span { color: var(--accent); }
.catalog-index {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.7rem;
}
.catalog-index li, .section-index li {
  position: relative;
  overflow: hidden;
  border: 1px solid var(--line);
  border-left: 3px solid var(--accent);
  border-radius: 0.8rem;
  background: var(--surface);
  box-shadow: 0 8px 24px rgba(39, 57, 94, 0.045);
  transition: transform 160ms ease, border-color 160ms ease, box-shadow 160ms ease;
}
.catalog-index .catalog-card--definition,
.section-index .catalog-card--definition { border-left-color: var(--definition); }
.catalog-index li:hover, .section-index li:hover {
  transform: translateY(-2px);
  border-color: hsla(28, 90%, 55%, 0.55);
  border-left-color: var(--accent);
  box-shadow: var(--shadow);
}
.catalog-index .catalog-card--definition:hover,
.section-index .catalog-card--definition:hover {
  border-color: color-mix(in srgb, var(--definition) 55%, var(--line));
  border-left-color: var(--definition);
}
.catalog-index a, .section-index a {
  display: flex;
  min-height: 6.25rem;
  padding: 0.85rem 2.4rem 0.85rem 1rem;
  flex-direction: column;
  align-items: flex-start;
  gap: 0.32rem;
  color: var(--ink);
  text-decoration: none;
}
.kind-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.28rem;
  color: var(--accent-strong);
  font-size: 0.65rem;
  font-weight: 800;
  letter-spacing: 0.08em;
  line-height: 1;
  text-transform: uppercase;
}
.kind-badge > span:first-child { font-size: 0.95rem; letter-spacing: 0; }
.kind-badge--definition { color: var(--definition); }
.card-title {
  font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif;
  font-size: 1.08rem;
  line-height: 1.22;
}
.card-attribution {
  margin-top: auto;
  color: var(--muted);
  font-size: 0.68rem;
  line-height: 1.25;
}
.card-arrow {
  position: absolute;
  right: 0.9rem;
  bottom: 0.75rem;
  color: var(--accent);
  font-size: 1rem;
}
.catalog-card--definition .card-arrow { color: var(--definition); }
.section-index { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 0.7rem; }
.section-index a { min-height: 5.8rem; }
.catalog-toolbar {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  gap: 0.7rem;
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 650;
}
.catalog-sort-label { margin-right: 0.1rem; }
.catalog-sort-option {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 0.38rem;
  cursor: pointer;
}
.catalog-sort-option input {
  position: absolute;
  width: 1px;
  height: 1px;
  opacity: 0;
}
.catalog-sort-indicator {
  display: grid;
  width: 0.85rem;
  height: 0.85rem;
  place-items: center;
  border: 1px solid currentColor;
  border-radius: 50%;
}
.catalog-sort-indicator::after {
  width: 0.43rem;
  height: 0.43rem;
  border-radius: 50%;
  background: currentColor;
  content: "";
  opacity: 0;
  transform: scale(0.5);
  transition: opacity 120ms ease, transform 120ms ease;
}
.catalog-sort-option input:checked + .catalog-sort-indicator::after {
  opacity: 1;
  transform: scale(1);
}
.catalog-sort-option input:focus-visible + .catalog-sort-indicator {
  outline: 2px solid currentColor;
  outline-offset: 3px;
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}
.hero-stats { margin: -0.4rem 0 0; color: var(--muted); font-size: 0.92rem; }
.hero-stats a { font-weight: 700; }
.group-intro { max-width: 46rem; margin: -0.4rem 0 1.1rem; color: var(--muted); font-size: 0.86rem; }
.card-top {
  display: flex;
  width: 100%;
  align-items: center;
  justify-content: space-between;
  gap: 0.6rem;
}
.card-counts { display: inline-flex; gap: 0.45rem; }
.count {
  display: inline-flex;
  align-items: center;
  gap: 0.18rem;
  padding: 0.08rem 0.42rem;
  border-radius: 999px;
  font-size: 0.68rem;
  font-weight: 750;
  line-height: 1.4;
}
.count--definition { background: var(--definition-soft); color: var(--definition); }
.count--theorem { background: var(--accent-soft); color: var(--accent-strong); }
.card-headlines, .card-context {
  color: var(--ink);
  font-size: 0.74rem;
  line-height: 1.35;
}
.card-headlines > span:first-child { color: var(--muted); font-weight: 700; }
.card-context { color: var(--muted); }
.catalog-card--headline { background: color-mix(in srgb, var(--accent-soft) 30%, var(--surface)); }
.declaration-label {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.5rem;
  margin: 0 0 0.35rem;
  font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif;
  font-size: 1.02rem;
  font-weight: 650;
}
.headline-tag {
  padding: 0.05rem 0.45rem;
  border-radius: 999px;
  background: var(--accent);
  color: white;
  font-family: ui-sans-serif, system-ui, sans-serif;
  font-size: 0.62rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.declarations li { scroll-margin-top: 6rem; }
.declarations li:target .lean-declaration { outline: 2px solid var(--accent); outline-offset: 2px; }
.results-page { width: min(100% - 2rem, 72rem); }
.results-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  margin: 1.5rem 0 1rem;
}
.results-toolbar .catalog-toolbar { margin: 0; }
.results-search input {
  width: min(28rem, 80vw);
  padding: 0.55rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 0.65rem;
  background: var(--surface-solid);
  color: var(--ink);
  font: inherit;
  font-size: 0.88rem;
}
.results-search input:focus-visible { outline: 3px solid hsla(28, 90%, 55%, 0.38); }
.results-table { width: 100%; border-collapse: collapse; font-size: 0.84rem; }
.results-table th {
  padding: 0.4rem 0.5rem;
  border-bottom: 2px solid var(--line);
  color: var(--muted);
  font-size: 0.7rem;
  letter-spacing: 0.08em;
  text-align: left;
  text-transform: uppercase;
}
.results-table td { padding: 0.5rem; border-bottom: 1px solid var(--line); vertical-align: top; }
.result-kind { width: 1.8rem; font-weight: 800; text-align: center; }
.result-kind--definition { color: var(--definition); }
.result-kind--theorem { color: var(--accent); }
.result-name { display: flex; flex-wrap: wrap; align-items: center; gap: 0.25rem 0.5rem; }
.result-name a { flex-basis: 100%; text-decoration: none; }
.result-label { font-family: ui-serif, Georgia, Cambria, "Times New Roman", serif; font-size: 0.98rem; }
.result-page { width: 14rem; }
.result-source { width: 4.5rem; text-align: right; }
.results-empty { color: var(--muted); }

.math-display { margin: 1.1rem 0; overflow-x: auto; overflow-y: hidden; }
.prose .katex { font-size: 1.05em; }

.breadcrumb { margin-bottom: 1.5rem; }
.breadcrumb a {
  display: inline-flex;
  align-items: center;
  gap: 0.35rem;
  color: var(--muted);
  font-size: 0.78rem;
  font-weight: 750;
  letter-spacing: 0.08em;
  text-decoration: none;
  text-transform: uppercase;
}
.breadcrumb a::before { content: "←"; color: var(--accent); font-size: 1rem; }
.lean-results { display: grid; gap: 0.75rem; margin-top: 3rem; }
.declaration-group {
  padding: clamp(0.95rem, 2vw, 1.25rem);
  border: 1px solid var(--line);
  border-top: 3px solid color-mix(in srgb, var(--accent) 68%, var(--line));
  border-radius: 1rem;
  background: var(--surface);
  box-shadow: 0 12px 35px rgba(39, 57, 94, 0.055);
}
.declaration-group--definition { border-top-color: var(--definition); }
.declaration-group h2 { margin: 0 0 1rem; font-size: 1.45rem; }
.declaration-group h2 span { color: var(--accent); font-family: ui-sans-serif, system-ui, sans-serif; }
.declaration-group--definition h2 span { color: var(--definition); }
.section-kicker { margin-bottom: 0.35rem; font-family: ui-sans-serif, system-ui, sans-serif; }
.declarations { display: grid; gap: 0.55rem; }
.declarations li {
  min-width: 0;
  padding: 0.75rem 0 0;
  border-top: 1px solid var(--line);
}
.declaration-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.8rem;
  margin-bottom: 0.65rem;
}
.declaration-name { color: var(--ink); font-weight: 700; }
.lean-declaration {
  margin: 0;
  padding: 0.72rem 0.85rem;
  border-color: color-mix(in srgb, var(--accent) 22%, var(--line));
  border-radius: 0.7rem;
  background: color-mix(in srgb, var(--accent-soft) 38%, var(--surface-solid));
  font-size: 0.78rem;
  line-height: 1.55;
  white-space: pre;
}
.declaration-group--definition .lean-declaration {
  border-color: color-mix(in srgb, var(--definition) 26%, var(--line));
  background: color-mix(in srgb, var(--definition-soft) 42%, var(--surface-solid));
}
.lean-declaration code { color: var(--ink); font-size: inherit; overflow-wrap: normal; }
.source {
  flex: none;
  padding: 0.3rem 0.6rem;
  border-radius: 999px;
  background: var(--accent-soft);
  font-size: 0.72rem;
  font-weight: 750;
  text-decoration: none;
}
.declaration-group--definition .source {
  background: var(--definition-soft);
  color: var(--definition);
}
code, pre { font-family: "SFMono-Regular", Consolas, "Liberation Mono", monospace; }
code { overflow-wrap: anywhere; font-size: 0.88em; }
.prose code { padding: 0.12rem 0.35rem; border-radius: 0.32rem; background: var(--accent-soft); }
pre {
  overflow-x: auto;
  padding: 1rem;
  border: 1px solid var(--line);
  border-radius: 0.75rem;
  background: var(--surface-solid);
}
.verification {
  margin-top: 2.5rem;
  padding-top: 1rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.76rem;
}
.verification span { font-weight: 750; text-transform: uppercase; letter-spacing: 0.06em; }
.verification code { color: var(--muted); }
.site-footer {
  width: min(100% - 2rem, 72rem);
  margin: 0 auto;
  padding: 1.5rem 0 2.5rem;
  border-top: 1px solid var(--line);
  color: var(--muted);
  font-size: 0.76rem;
}

@media (max-width: 44rem) {
  .site-header nav { min-height: 4rem; gap: 0.5rem; }
  .brand-copy small { display: none; }
  .nav-links { gap: 0; }
  .nav-links a { padding-inline: 0.48rem; font-size: 0.8rem; }
  .nav-links a:last-child { display: none; }
  .catalog-index { grid-template-columns: 1fr; }
  .section-index { grid-template-columns: 1fr; }
  .catalog-index a { min-height: 5.8rem; }
  .declaration-meta { align-items: flex-start; flex-direction: column; }
  .result-page, .result-source { display: none; }
  .source { align-self: flex-start; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .catalog-index li, .section-index li, .catalog-sort-indicator::after { transition: none; }
}

@media (prefers-color-scheme: dark) {
  :root {
    --ink: #f5eee8;
    --muted: #c1afa2;
    --paper: #17120f;
    --surface: rgba(36, 28, 23, 0.9);
    --surface-solid: #241c17;
    --line: #4a392e;
    --accent: #ff9850;
    --accent-strong: #ffc08f;
    --accent-soft: #3b2417;
    --definition: #79b8f3;
    --definition-soft: #172c3f;
    --eyebrow: #f2a064;
    --shadow: 0 20px 55px rgba(0, 0, 0, 0.32);
  }
  .site-header {
    border-bottom-color: rgba(74, 57, 46, 0.92);
    background: rgba(23, 18, 15, 0.86);
  }
  .catalog-index li, .section-index li, .declaration-group { box-shadow: none; }
}