@import url('https://fonts.googleapis.com/css2?family=Fraunces:opsz,wght,SOFT@9..144,300..700,0..100&family=IBM+Plex+Mono:wght@400;500;600&family=IBM+Plex+Sans:wght@400;500;600&display=swap');

:root {
  /* Paper / ink palette */
  --paper:    #f4eee0;
  --paper-2:  #faf5e8;
  --paper-3:  #ebe2cc;
  --ink:      #1a1614;
  --ink-2:    #3d3530;
  --ink-3:    #6e655a;
  --ink-4:    #968b7c;
  --rule:     #d8cdb6;
  --hairline: #e6dec9;

  --accent:        #1f4040;
  --accent-2:      #2d5959;
  --accent-pale:   #d4dcdc;
  --accent-tint:   color-mix(in oklch, var(--accent) 12%, var(--paper));

  /* Engine colors — warmed against the paper background */
  --eng-gsheets:      #2f7a3f;
  --eng-excel:        #1d4e8a;
  --eng-lattice:      #277076;
  --eng-ironcalc:     #a8451c;
  --eng-hyperformula: #5d2a8a;
  --eng-libreoffice:  #1f3475;
  --eng-formulas:     #107075;
  --eng-pycel:        #8a5210;

  /* Cause palette — muted, named like pigments */
  --cause-missing-function:  #5a554c;
  --cause-error-code:        #b2491a;
  --cause-precision:         #1d4e8a;
  --cause-format-rendering:  #6d2d8a;
  --cause-arg-semantics:     #a83020;
  --cause-shape:             #92710a;
  --cause-array-orientation: #097780;
  --cause-null-vs-zero:      #5b258c;
  --cause-array-handling:    #921832;
  --cause-intentional-spec:  #1f5d3a;
  --cause-error-attribution: #882424;
  --cause-locale:            #94391d;
  --cause-recalc-semantics:  #1c3878;
  --cause-unimplemented-edge:#691438;
  --cause-version-skew:      #495565;
  --cause-missing-arg-form:  #4f238e;
  --cause-argument-arity:    #8a1d3f;

  /* Verdict palette — used on compare page */
  --verdict-match:        var(--eng-gsheets);
  --verdict-matches-some: var(--cause-precision);
  --verdict-diverge:      var(--cause-error-code);
  --verdict-matches-none: var(--cause-arg-semantics);

  /* Type system */
  --font-display: "Fraunces", "Iowan Old Style", Georgia, serif;
  --font-body:    "IBM Plex Sans", system-ui, -apple-system, sans-serif;
  --font-mono:    "IBM Plex Mono", "JetBrains Mono", "SF Mono", Menlo, monospace;

  /* Rhythm */
  --gutter: 2rem;
  --rule-w: 1px;
}

/* Dark palette: applied via prefers-color-scheme by default, OR explicitly via data-theme="dark". */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) { color-scheme: dark; }
  :root:not([data-theme="light"]) {
    --paper:    #161310;
    --paper-2:  #1f1b16;
    --paper-3:  #2a241d;
    --ink:      #f0e9d8;
    --ink-2:    #c8c0ad;
    --ink-3:    #948b78;
    --ink-4:    #6d6557;
    --rule:     #3a322a;
    --hairline: #2a241d;

    --accent:        #6ba0a0;
    --accent-2:      #4d8585;
    --accent-pale:   #2a3a3a;
    --accent-tint:   color-mix(in oklch, var(--accent) 18%, var(--paper));

    --eng-gsheets:      #6ec57b;
    --eng-excel:        #6a9bd6;
    --eng-lattice:      #5fc0c5;
    --eng-ironcalc:     #e88c5e;
    --eng-hyperformula: #b27ad8;
    --eng-libreoffice:  #6e8edd;
    --eng-formulas:     #5cb8bd;
    --eng-pycel:        #d8a06a;

    --cause-missing-function:  #b1aa9a;
    --cause-error-code:        #ec9663;
    --cause-precision:         #6a9bd6;
    --cause-format-rendering:  #b482d6;
    --cause-arg-semantics:     #e58370;
    --cause-shape:             #d4b860;
    --cause-array-orientation: #5cbac1;
    --cause-null-vs-zero:      #a577d6;
    --cause-array-handling:    #d87690;
    --cause-intentional-spec:  #79c490;
    --cause-error-attribution: #d77878;
    --cause-locale:            #d68866;
    --cause-recalc-semantics:  #7494d2;
    --cause-unimplemented-edge:#c87aa8;
    --cause-version-skew:      #aab1ba;
    --cause-missing-arg-form:  #a583d6;
    --cause-argument-arity:    #d77a98;
  }
}

/* Manual override: data-theme="dark" forces dark even when system prefers light. */
:root[data-theme="dark"] { color-scheme: dark; }
:root[data-theme="dark"] {
  --paper:    #161310;
  --paper-2:  #1f1b16;
  --paper-3:  #2a241d;
  --ink:      #f0e9d8;
  --ink-2:    #c8c0ad;
  --ink-3:    #948b78;
  --ink-4:    #6d6557;
  --rule:     #3a322a;
  --hairline: #2a241d;

  --accent:        #6ba0a0;
  --accent-2:      #4d8585;
  --accent-pale:   #2a3a3a;
  --accent-tint:   color-mix(in oklch, var(--accent) 18%, var(--paper));

  --eng-gsheets:      #6ec57b;
  --eng-excel:        #6a9bd6;
  --eng-lattice:      #5fc0c5;
  --eng-ironcalc:     #e88c5e;
  --eng-hyperformula: #b27ad8;
  --eng-libreoffice:  #6e8edd;
  --eng-formulas:     #5cb8bd;
  --eng-pycel:        #d8a06a;

  --cause-missing-function:  #b1aa9a;
  --cause-error-code:        #ec9663;
  --cause-precision:         #6a9bd6;
  --cause-format-rendering:  #b482d6;
  --cause-arg-semantics:     #e58370;
  --cause-shape:             #d4b860;
  --cause-array-orientation: #5cbac1;
  --cause-null-vs-zero:      #a577d6;
  --cause-array-handling:    #d87690;
  --cause-intentional-spec:  #79c490;
  --cause-error-attribution: #d77878;
  --cause-locale:            #d68866;
  --cause-recalc-semantics:  #7494d2;
  --cause-unimplemented-edge:#c87aa8;
  --cause-version-skew:      #aab1ba;
  --cause-missing-arg-form:  #a583d6;
  --cause-argument-arity:    #d77a98;
}

/* ── Base ─────────────────────────────────────────────────────────── */

*, *::before, *::after { box-sizing: border-box; }

html {
  font-family: var(--font-body);
  font-size: 15.5px;
  font-feature-settings: "ss01", "cv11", "tnum" 0;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  position: relative;
  min-height: 100vh;
  /* Subtle vignette + paper tint */
  background-image:
    radial-gradient(ellipse 1200px 600px at 25% -5%, var(--paper-2) 0%, transparent 60%),
    radial-gradient(ellipse 800px 400px at 95% 105%, var(--accent-tint) 0%, transparent 70%);
}

/* Paper grain — fixed overlay, very subtle */
body::before {
  content: '';
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  opacity: 0.4;
  background-image: url("data:image/svg+xml;utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='180' height='180' viewBox='0 0 180 180'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='2' seed='3'/%3E%3CfeColorMatrix values='0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0.04 0'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  mix-blend-mode: multiply;
}
@media (prefers-color-scheme: dark) {
  body::before { mix-blend-mode: screen; opacity: 0.5; }
}

main {
  max-width: 1340px;
  margin: 0 auto;
  padding: 3rem var(--gutter) 6rem;
  position: relative;
  z-index: 1;
}

a {
  color: var(--accent);
  text-decoration: none;
  text-underline-offset: 2px;
  text-decoration-thickness: 1px;
}
a:hover { text-decoration: underline; }

code {
  font-family: var(--font-mono);
  font-size: 0.88em;
  letter-spacing: -0.005em;
}
code.formula {
  background: var(--paper-2);
  padding: 0.1em 0.45em;
  border: 1px solid var(--hairline);
  border-radius: 3px;
  white-space: pre-wrap;
  word-break: break-word;
}

/* ── Display typography ───────────────────────────────────────────── */

h1 {
  font-family: var(--font-display);
  font-variation-settings: "opsz" 144, "wght" 380, "SOFT" 30;
  font-size: clamp(2.4rem, 4.4vw, 3.6rem);
  font-weight: 380;
  letter-spacing: -0.022em;
  line-height: 1.04;
  margin: 0 0 0.5rem;
  color: var(--ink);
}

h2 {
  font-family: var(--font-display);
  font-variation-settings: "opsz" 36, "wght" 480, "SOFT" 0;
  font-size: 1.45rem;
  font-weight: 480;
  letter-spacing: -0.014em;
  margin: 0 0 0.6rem;
}

.eyebrow {
  display: block;
  font-family: var(--font-mono);
  font-size: 0.7rem;
  font-weight: 500;
  letter-spacing: 0.06em;
  color: var(--ink-3);
  margin-bottom: 0.5rem;
  text-transform: lowercase;
}

.dek {
  font-family: var(--font-body);
  font-size: 0.98rem;
  line-height: 1.5;
  color: var(--ink-2);
  max-width: 64ch;
  margin: 0.5rem 0 0;
}

/* ── Header / nav ─────────────────────────────────────────────────── */

header {
  margin-bottom: 2.5rem;
  padding-bottom: 1.75rem;
  border-bottom: var(--rule-w) solid var(--rule);
}
header .meta {
  font-size: 0.92rem;
  color: var(--ink-3);
  margin: 0.6rem 0 0;
  font-variant-numeric: tabular-nums;
}
header .summary {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.5;
  color: var(--ink-2);
  max-width: 64ch;
  margin: 0.5rem 0 0;
}
nav {
  font-size: 0.85rem;
}
nav a {
  color: var(--ink-3);
  letter-spacing: 0.02em;
}
nav a:hover { color: var(--accent); }

.page-top {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 1.25rem;
}
.page-top-right {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.flat-nav {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.85rem;
}
.flat-nav a {
  color: var(--ink-3);
  letter-spacing: 0.01em;
}
.flat-nav a:hover { color: var(--accent); }
.flat-nav .nav-sep { color: var(--ink-4); user-select: none; }

.theme-toggle {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  padding: 0;
  background: transparent;
  border: 1px solid var(--rule);
  color: var(--ink-2);
  cursor: pointer;
  font-family: var(--font-mono);
  font-size: 1.05rem;
  line-height: 1;
  transition: border-color 160ms ease, color 160ms ease, background 160ms ease;
}
.theme-toggle:hover {
  border-color: var(--accent);
  color: var(--accent);
}
/* Default (light): show moon ("click to switch to dark"). */
.theme-toggle .sun { display: none; }
.theme-toggle .moon { display: inline; }
/* When effective theme is dark, swap icons. */
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .theme-toggle .moon { display: none; }
  :root:not([data-theme="light"]) .theme-toggle .sun  { display: inline; }
}
:root[data-theme="dark"] .theme-toggle .moon { display: none; }
:root[data-theme="dark"] .theme-toggle .sun  { display: inline; }

/* ── Filters (index page) ─────────────────────────────────────────── */

.filters {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  margin-bottom: 1.75rem;
  padding: 0.75rem 1rem;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  /* Establish a stacking context above the table-wrap so dropdowns sit on top. */
  position: relative;
  z-index: 20;
}
.filters input[type="search"] {
  flex: 1;
  min-width: 240px;
  padding: 0.55rem 0.75rem;
  font: 0.95rem/1 var(--font-body);
  background: transparent;
  color: var(--ink);
  border: none;
  border-bottom: 1px solid var(--rule);
  outline: none;
  letter-spacing: -0.005em;
}
.filters input[type="search"]:focus { border-bottom-color: var(--accent); }
.filters input[type="search"]::placeholder { color: var(--ink-4); }

.filters details { position: relative; }
.filters summary {
  cursor: pointer;
  padding: 0.5rem 0.85rem;
  background: transparent;
  border: 1px solid var(--rule);
  font-size: 0.88rem;
  letter-spacing: -0.005em;
  list-style: none;
  user-select: none;
  transition: border-color 140ms ease, background 140ms ease;
}
.filters summary::-webkit-details-marker { display: none; }
.filters summary::after { content: "▾"; margin-left: 0.5em; color: var(--ink-3); font-size: 0.75em; }
.filters details[open] summary { background: var(--paper); border-color: var(--ink-3); }
.filters details summary:hover { border-color: var(--ink-3); }

.filter-group {
  position: absolute;
  top: calc(100% + 4px);
  left: 0;
  margin-top: 0;
  padding: 0.4rem;
  min-width: 220px;
  max-height: 360px;
  overflow-y: auto;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  z-index: 30;
  box-shadow: 0 12px 32px rgba(0,0,0,0.08), 0 2px 4px rgba(0,0,0,0.04);
}
.filter-group label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  padding: 0.35rem 0.5rem;
  font-size: 0.88rem;
  cursor: pointer;
  border-radius: 2px;
}
.filter-group label:hover { background: var(--paper-3); }
.filter-group label:has(input:checked) { background: var(--accent-tint); color: var(--ink); }
.filter-group input { accent-color: var(--accent); }
.filter-group .count {
  margin-left: auto;
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: 0.78em;
  font-feature-settings: "tnum";
}

.filters button {
  padding: 0.5rem 0.85rem;
  font: 0.88rem var(--font-body);
  background: transparent;
  color: var(--ink-3);
  border: 1px solid transparent;
  cursor: pointer;
  letter-spacing: 0.02em;
}
.filters button:hover { color: var(--ink); border-color: var(--rule); }

.result-count {
  margin-left: auto;
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-feature-settings: "tnum";
  font-variant-numeric: tabular-nums;
}

/* ── Index table (DV catalogue) ───────────────────────────────────── */

.table-wrap {
  background: var(--paper-2);
  border: 1px solid var(--rule);
  overflow: auto;
}
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.94rem;
}
thead th {
  font-weight: 500;
  font-size: 0.72rem;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-3);
  text-align: left;
  padding: 0.85rem 1rem;
  border-bottom: 1px solid var(--rule);
  background: var(--paper-2);
  position: sticky;
  top: 0;
  z-index: 5;
  cursor: pointer;
  user-select: none;
}
thead th[data-sort]:hover { color: var(--ink); }
tbody td {
  padding: 0.65rem 1rem;
  border-bottom: 1px solid var(--hairline);
  vertical-align: top;
}
tbody tr { transition: background 100ms ease; }
tbody tr:hover { background: var(--accent-tint); }
tbody tr:last-child td { border-bottom: none; }

.num {
  text-align: right;
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  font-variant-numeric: tabular-nums;
}
.more { color: var(--ink-3); font-size: 0.85em; font-style: italic; }

#dv-table td:first-child a {
  font-family: var(--font-mono);
  font-size: 0.86em;
  color: var(--accent);
  font-weight: 500;
  letter-spacing: -0.01em;
}

/* ── Chips ────────────────────────────────────────────────────────── */

.chip {
  display: inline-block;
  padding: 0.18em 0.6em;
  border-radius: 0;
  font-family: var(--font-body);
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  white-space: nowrap;
  margin-right: 0.3rem;
  margin-bottom: 0.2rem;
  border: 1px solid transparent;
}
.chip.cause {
  background: transparent;
  border-color: currentColor;
  color: var(--cause-missing-function);
}
.chip.cause-missing-function   { color: var(--cause-missing-function); }
.chip.cause-error-code         { color: var(--cause-error-code); }
.chip.cause-precision          { color: var(--cause-precision); }
.chip.cause-format-rendering   { color: var(--cause-format-rendering); }
.chip.cause-arg-semantics      { color: var(--cause-arg-semantics); }
.chip.cause-shape              { color: var(--cause-shape); }
.chip.cause-array-orientation  { color: var(--cause-array-orientation); }
.chip.cause-null-vs-zero       { color: var(--cause-null-vs-zero); }
.chip.cause-array-handling     { color: var(--cause-array-handling); }
.chip.cause-intentional-spec   { color: var(--cause-intentional-spec); }
.chip.cause-error-attribution  { color: var(--cause-error-attribution); }
.chip.cause-locale             { color: var(--cause-locale); }
.chip.cause-recalc-semantics   { color: var(--cause-recalc-semantics); }
.chip.cause-unimplemented-edge { color: var(--cause-unimplemented-edge); }
.chip.cause-version-skew       { color: var(--cause-version-skew); }
.chip.cause-missing-arg-form   { color: var(--cause-missing-arg-form); }
.chip.cause-argument-arity     { color: var(--cause-argument-arity); }

.chip.eng {
  background: transparent;
  border-color: currentColor;
}
.chip.eng-gsheets      { color: var(--eng-gsheets); }
.chip.eng-excel        { color: var(--eng-excel); }
.chip.eng-lattice      { color: var(--eng-lattice); }
.chip.eng-ironcalc     { color: var(--eng-ironcalc); }
.chip.eng-hyperformula { color: var(--eng-hyperformula); }
.chip.eng-libreoffice  { color: var(--eng-libreoffice); }
.chip.eng-formulas     { color: var(--eng-formulas); }
.chip.eng-pycel        { color: var(--eng-pycel); }

.chip.category {
  border-color: var(--ink-4);
  color: var(--ink-3);
  font-style: italic;
  font-weight: 400;
}

/* ── DV detail page ───────────────────────────────────────────────── */

.metadata {
  margin: 1.5rem 0 2rem;
}
.metadata dl {
  display: grid;
  grid-template-columns: 14ch 1fr;
  gap: 0.55rem 1.5rem;
  margin: 0;
  padding: 1rem 1.25rem;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  font-size: 0.95rem;
}
.metadata dt {
  color: var(--ink-3);
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  padding-top: 0.18em;
}
.metadata dd { margin: 0; line-height: 1.5; }
.metadata dd code {
  background: var(--paper-3);
  padding: 0.1em 0.4em;
  border-radius: 2px;
  word-break: break-all;
}

section { margin-bottom: 2.25rem; }
section h2 {
  display: flex;
  align-items: baseline;
  gap: 0.5em;
}
section h2 + p { margin-top: 0.25rem; }

.subjects { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.subject-pill {
  display: inline-block;
  padding: 0.2em 0.7em;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  font-family: var(--font-mono);
  font-size: 0.82rem;
  color: var(--ink);
  letter-spacing: -0.005em;
  transition: border-color 140ms ease, color 140ms ease;
}
.subject-pill:hover {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

.muted { color: var(--ink-3); font-style: italic; }

/* ── Per-engine verdict table on DV detail pages ──────────────────── */

.tests-table-wrap {
  overflow-x: auto;
  background: var(--paper-2);
  border: 1px solid var(--rule);
}
table.tests-engines {
  font-size: 0.85rem;
  min-width: 100%;
}
table.tests-engines thead th {
  white-space: nowrap;
  font-size: 0.68rem;
  letter-spacing: 0.13em;
  padding: 0.7rem 0.7rem;
  border-bottom: 1px solid var(--rule);
}
table.tests-engines th.engine-col { padding: 0.5rem 0.6rem; text-align: center; }
table.tests-engines th.engine-col.in-cluster {
  background: var(--accent-tint);
  border-bottom: 2px solid var(--accent);
}
table.tests-engines td {
  vertical-align: middle;
  white-space: nowrap;
  border-bottom: 1px solid var(--hairline);
  padding: 0.5rem 0.7rem;
}
table.tests-engines tbody tr:hover { background: var(--accent-tint); }
table.tests-engines td.test-id {
  font-family: var(--font-mono);
  font-size: 0.82em;
}
table.tests-engines td.canonical {
  font-family: var(--font-mono);
  font-size: 0.82em;
  color: var(--ink-3);
  border-right: 1px solid var(--rule);
  padding-right: 1rem;
}

table.tests-engines td.engine-cell {
  text-align: center;
  font-family: var(--font-mono);
  font-size: 0.78em;
  position: relative;
}
table.tests-engines td.engine-cell .engine-tag { display: none; }
table.tests-engines td.engine-cell .engine-value {
  display: inline-block;
  max-width: 11ch;
  overflow: hidden;
  text-overflow: ellipsis;
}

.engine-cell.verdict-match    { color: var(--ink-3); }
.engine-cell.verdict-match .engine-value { color: var(--ink-2); }
.engine-cell.verdict-diverge {
  color: var(--cause-error-code);
  font-weight: 500;
  background: color-mix(in oklch, var(--cause-error-code) 8%, transparent);
}
.engine-cell.verdict-no-data { color: var(--ink-4); }
.engine-cell.in-cluster {
  box-shadow: inset 0 -2px 0 0 var(--accent);
}

.section-header {
  display: flex;
  flex-wrap: wrap;
  align-items: baseline;
  justify-content: space-between;
  gap: 1rem;
  margin-bottom: 0.75rem;
}

.legend {
  font-size: 0.78rem;
  color: var(--ink-3);
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.85rem;
}
.legend-item { display: inline-flex; align-items: center; gap: 0.4em; font-feature-settings: "tnum"; }
.swatch {
  display: inline-block;
  width: 10px;
  height: 10px;
  border-radius: 0;
  border: 1px solid var(--rule);
}
.swatch.verdict-match    { background: transparent; border-color: var(--verdict-match); }
.swatch.verdict-diverge  { background: color-mix(in oklch, var(--cause-error-code) 8%, var(--paper-2)); border-color: var(--cause-error-code); }
.swatch.verdict-no-data  { background: var(--paper); }
.swatch.in-cluster       { background: var(--paper-2); box-shadow: inset 0 -2px 0 0 var(--accent); border: 1px solid var(--rule); }

/* ── Compare page ─────────────────────────────────────────────────── */

.compare-config {
  background: var(--paper-2);
  border: 1px solid var(--rule);
  padding: 1.25rem 1.5rem;
  margin-bottom: 2rem;
}
.presets {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  margin-bottom: 1rem;
  padding-bottom: 1rem;
  border-bottom: 1px solid var(--hairline);
}
.presets-label {
  color: var(--ink-3);
  font-size: 0.72rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 500;
}
.preset {
  padding: 0.5rem 0.9rem;
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 0;
  font: 0.88rem var(--font-body);
  cursor: pointer;
  letter-spacing: -0.005em;
  transition: border-color 140ms ease, color 140ms ease, background 140ms ease;
}
.preset:hover { border-color: var(--accent); color: var(--accent); }

.compare-pickers {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  align-items: center;
}
.compare-pickers > label {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.88rem;
}
.compare-pickers > label > span {
  font-size: 0.7rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 500;
  color: var(--ink-3);
  padding: 0 0.5rem;
}
/* Match the <details> summary look used in the catalogue filters. */
.compare-pickers select {
  padding: 0.5rem 1.8rem 0.5rem 0.85rem;
  font: 0.88rem var(--font-body);
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--rule);
  border-radius: 0;
  min-width: 140px;
  letter-spacing: -0.005em;
  cursor: pointer;
  appearance: none;
  -webkit-appearance: none;
  background-image: linear-gradient(45deg, transparent 50%, var(--ink-3) 50%),
                    linear-gradient(135deg, var(--ink-3) 50%, transparent 50%);
  background-position: calc(100% - 14px) center, calc(100% - 9px) center;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
}
.compare-pickers select:hover { border-color: var(--ink-3); }
.compare-pickers select:focus { outline: none; border-color: var(--accent); }

fieldset.ref-picker {
  border: 1px solid var(--rule);
  padding: 0.5rem 0.75rem 0.4rem;
  margin: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.3rem;
  align-items: center;
}
fieldset.ref-picker legend {
  font-size: 0.7rem;
  color: var(--ink-3);
  padding: 0 0.5rem;
  letter-spacing: 0.13em;
  text-transform: uppercase;
  font-weight: 500;
}
.engine-pick {
  display: inline-flex !important;
  align-items: center;
  gap: 0.3rem !important;
  padding: 0.25rem 0.55rem;
  cursor: pointer;
  border: 1px solid transparent;
  transition: border-color 120ms ease;
}
.engine-pick:hover { border-color: var(--rule); }
.engine-pick:has(input:checked) { border-color: var(--accent); background: var(--accent-tint); }
.engine-pick input { accent-color: var(--accent); margin-right: 0.15rem; }

.copy-link {
  margin-left: auto;
  padding: 0.5rem 0.85rem;
  background: transparent;
  border: 1px solid var(--rule);
  color: var(--ink-3);
  border-radius: 0;
  font: 0.82rem var(--font-body);
  cursor: pointer;
  letter-spacing: 0.02em;
}
.copy-link:hover { color: var(--ink); border-color: var(--ink-3); }

/* Compare summary tiles — large editorial figures */
.summary-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 0;
  margin-bottom: 2.25rem;
  border: 1px solid var(--rule);
  background: var(--paper-2);
}
.summary-tile {
  padding: 1.25rem 1.4rem;
  border-right: 1px solid var(--hairline);
  border-bottom: 1px solid var(--hairline);
  position: relative;
}
.summary-tile:last-child { border-right: none; }
.summary-tile.primary { background: var(--accent-tint); }
.summary-tile.primary .summary-num { color: var(--accent); }
.summary-tile.warn   .summary-num { color: var(--cause-error-code); }
.summary-tile.danger .summary-num { color: var(--cause-arg-semantics); }
.summary-tile.muted  { opacity: 0.85; }

.summary-num {
  font-family: var(--font-display);
  font-variation-settings: "opsz" 144, "wght" 380, "SOFT" 0;
  font-size: 2.5rem;
  font-weight: 380;
  line-height: 1;
  letter-spacing: -0.025em;
  font-feature-settings: "tnum", "lnum";
}
.summary-num .pct {
  font-size: 0.45em;
  font-weight: 400;
  margin-left: 0.15em;
  opacity: 0.7;
  font-variation-settings: "wght" 360;
}
.summary-label {
  margin-top: 0.5rem;
  font-size: 0.86rem;
  line-height: 1.4;
}
.summary-label .muted {
  display: block;
  margin-top: 0.15rem;
  color: var(--ink-3);
  font-size: 0.92em;
  font-style: italic;
}

/* Verdict chips on compare */
.filter-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
}
.verdict-chip {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  padding: 0.35rem 0.7rem;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  font-size: 0.82rem;
  cursor: pointer;
  user-select: none;
  letter-spacing: -0.005em;
}
.verdict-chip:hover { border-color: var(--ink-3); }
.verdict-chip:has(input:checked) {
  background: var(--paper);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 500;
}
.verdict-chip input { display: none; }
.verdict-chip .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink-4);
}
.verdict-chip .count {
  color: var(--ink-3);
  font-family: var(--font-mono);
  font-feature-settings: "tnum";
  font-size: 0.78em;
}
.verdict-chip.verdict-match .dot           { background: var(--verdict-match); }
.verdict-chip.verdict-matches-some .dot    { background: var(--verdict-matches-some); }
.verdict-chip.verdict-diverge .dot         { background: var(--verdict-diverge); }
.verdict-chip.verdict-matches-none .dot    { background: var(--verdict-matches-none); }
.verdict-chip.verdict-no-target-data .dot,
.verdict-chip.verdict-no-ref-data .dot     { background: var(--ink-4); }

.verdict-tag {
  display: inline-block;
  padding: 0.15em 0.55em;
  border-radius: 0;
  font-size: 0.74rem;
  font-weight: 500;
  letter-spacing: 0.01em;
  background: transparent;
  border: 1px solid var(--rule);
  color: var(--ink);
}
.verdict-tag.verdict-match {
  border-color: var(--verdict-match);
  color: var(--verdict-match);
}
.verdict-tag.verdict-matches-some {
  border-color: var(--verdict-matches-some);
  color: var(--verdict-matches-some);
}
.verdict-tag.verdict-diverge {
  border-color: var(--verdict-diverge);
  color: var(--verdict-diverge);
}
.verdict-tag.verdict-matches-none {
  border-color: var(--verdict-matches-none);
  color: var(--verdict-matches-none);
  background: color-mix(in oklch, var(--verdict-matches-none) 6%, transparent);
}

#compare-table {
  font-size: 0.88rem;
  font-feature-settings: "tnum";
}
#compare-table td.target-val,
#compare-table td.expected-val,
#compare-table td.ref-vals {
  font-family: var(--font-mono);
  font-size: 0.82em;
}
#compare-table td.expected-val { color: var(--ink-3); }
#compare-table td.ref-vals {
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem 0.7rem;
  align-items: center;
}
.ref-val { display: inline-flex; align-items: center; gap: 0.3rem; }
.ref-val.no-data { opacity: 0.4; }
.ref-val .chip {
  font-size: 0.7rem;
  padding: 0 0.4em;
  margin: 0;
}
.dv-links a {
  font-family: var(--font-mono);
  font-size: 0.85em;
  margin-right: 0.5em;
}

.hint {
  padding: 1.25rem;
  background: var(--paper-2);
  border: 1px solid var(--rule);
  font-style: italic;
  font-family: var(--font-display);
  font-variation-settings: "opsz" 14, "wght" 380, "SOFT" 50;
  color: var(--ink-2);
}

/* About page article */
.prose {
  max-width: 64ch;
  font-size: 1.02rem;
  line-height: 1.65;
  color: var(--ink);
}
.prose h2 {
  font-size: 1.35rem;
  margin: 2rem 0 0.6rem;
  font-variation-settings: "opsz" 36, "wght" 460;
}
.prose h2:first-child { margin-top: 0; }
.prose p {
  margin: 0 0 1rem;
}
.prose ul {
  margin: 0 0 1rem;
  padding-left: 1.2rem;
}
.prose ul li { margin-bottom: 0.4rem; }
.prose strong { font-weight: 600; }
.prose code {
  background: var(--paper-2);
  padding: 0.05em 0.35em;
  border: 1px solid var(--hairline);
  border-radius: 2px;
  font-size: 0.9em;
}
.prose dl.prose-dl {
  display: grid;
  grid-template-columns: max-content 1fr;
  gap: 0.8rem 1.5rem;
  margin: 0 0 1.25rem;
  padding: 0;
}
.prose dl.prose-dl dt {
  font-weight: 500;
  color: var(--ink);
  padding-top: 0.1em;
}
.prose dl.prose-dl dt a { color: var(--accent); }
.prose dl.prose-dl dd { margin: 0; color: var(--ink-2); }
@media (max-width: 640px) {
  .prose dl.prose-dl { grid-template-columns: 1fr; gap: 0.25rem 0; }
  .prose dl.prose-dl dd { margin-bottom: 0.8rem; }
}
.truncated {
  text-align: center;
  padding: 0.85rem;
  color: var(--ink-3);
  font-style: italic;
}

/* Responsive tweaks */
@media (max-width: 720px) {
  main { padding: 1.5rem 1.25rem 4rem; }
  .summary-grid { grid-template-columns: 1fr 1fr; }
  .summary-tile:nth-child(2n) { border-right: none; }
  .metadata dl { grid-template-columns: 1fr; gap: 0.15rem 0; padding: 1rem; }
  .metadata dt { padding-top: 0.6rem; }
}

/* Subtle entrance animation on first load */
@keyframes rise {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}
header, .filters, .summary-grid, .compare-config, .table-wrap, .tests-table-wrap, .metadata {
  animation: rise 320ms ease-out both;
}
.filters         { animation-delay: 60ms; }
.summary-grid    { animation-delay: 80ms; }
.compare-config  { animation-delay: 80ms; }
.table-wrap, .tests-table-wrap { animation-delay: 140ms; }
.metadata        { animation-delay: 60ms; }

/* Reduce motion */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
}