:root {
  color-scheme: light;
  --page: #f9f9f7;
  --surface-1: #fcfcfb;
  --text-primary: #0b0b0b;
  --text-secondary: #52514e;
  --text-muted: #898781;
  --grid: #e1e0d9;
  --axis: #c3c2b7;
  --border: rgba(11, 11, 11, 0.10);
  --wash: rgba(42, 120, 214, 0.08);
  --series-1: #2a78d6;
  --series-2: #eb6834;
  --series-3: #1baf7a;
  --series-4: #eda100;
  --warning: #9a6700;
  --font: system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --page: #0d0d0d;
    --surface-1: #1a1a19;
    --text-primary: #f0efec;
    --text-secondary: #c3c2b7;
    --text-muted: #898781;
    --grid: #2c2c2a;
    --axis: #383835;
    --border: rgba(255, 255, 255, 0.10);
    --wash: rgba(57, 135, 229, 0.14);
    --series-1: #3987e5;
    --series-2: #d95926;
    --series-3: #199e70;
    --series-4: #c98500;
    --warning: #fab219;
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --page: #0d0d0d;
  --surface-1: #1a1a19;
  --text-primary: #f0efec;
  --text-secondary: #c3c2b7;
  --text-muted: #898781;
  --grid: #2c2c2a;
  --axis: #383835;
  --border: rgba(255, 255, 255, 0.10);
  --wash: rgba(57, 135, 229, 0.14);
  --series-1: #3987e5;
  --series-2: #d95926;
  --series-3: #199e70;
  --series-4: #c98500;
  --warning: #fab219;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--page);
  color: var(--text-primary);
  font-family: var(--font);
  line-height: 1.5;
}

.page-header,
main {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 16px;
}

.page-header { padding-top: 40px; padding-bottom: 8px; }

h1 { font-size: 1.75rem; margin: 0 0 8px; letter-spacing: -0.01em; }
h2 { font-size: 1.05rem; margin: 0; }

.lede { color: var(--text-secondary); max-width: 70ch; margin: 0; }

code { font-family: var(--mono); font-size: 0.9em; }

a { color: var(--series-1); }

.cell-picker {
  display: flex;
  align-items: center;
  gap: 12px;
  margin: 24px 0 16px;
  flex-wrap: wrap;
}

.picker-label { color: var(--text-secondary); font-size: 0.9rem; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; }

.chip {
  font: inherit;
  font-size: 0.9rem;
  font-variant-numeric: tabular-nums;
  min-width: 44px;
  padding: 4px 10px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-1);
  color: var(--text-primary);
  cursor: pointer;
}

.chip:hover { background: var(--wash); }

.chip[aria-pressed="true"] {
  background: var(--text-primary);
  border-color: var(--text-primary);
  color: var(--surface-1);
}

.layout {
  display: grid;
  grid-template-columns: minmax(280px, 380px) minmax(0, 1fr);
  gap: 16px;
  align-items: start;
}

@media (max-width: 820px) {
  .layout { grid-template-columns: minmax(0, 1fr); }
}

.card {
  background: var(--surface-1);
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  min-width: 0;
}

.card-head { margin-bottom: 8px; }

.sub { margin: 2px 0 0; color: var(--text-secondary); font-size: 0.9rem; }

.legend {
  list-style: none;
  margin: 0 0 8px;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 4px 16px;
  font-size: 0.85rem;
  color: var(--text-secondary);
}

.legend li { display: flex; align-items: center; gap: 6px; }

.key { display: inline-block; flex: none; }
.key-dot { width: 8px; height: 8px; border-radius: 50%; background: var(--text-muted); }
.key-line { width: 16px; height: 2px; border-radius: 1px; background: var(--key); }

.toggles button {
  font: inherit;
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 2px 8px;
  margin: 0 -8px;
  border: 0;
  border-radius: 6px;
  background: none;
  color: var(--text-secondary);
  cursor: pointer;
}

.toggles button:hover { background: var(--wash); }
.toggles button[aria-pressed="false"] { color: var(--text-muted); text-decoration: line-through; }
.toggles button[aria-pressed="false"] .key { opacity: 0.3; }

.chart-wrap { position: relative; }
.chart-wrap svg { display: block; width: 100%; height: auto; overflow: visible; }

.grid-line { stroke: var(--grid); stroke-width: 1; }
.axis-line { stroke: var(--axis); stroke-width: 1; }
.tick { fill: var(--text-muted); font-size: 11px; font-variant-numeric: tabular-nums; }
.axis-title { fill: var(--text-muted); font-size: 11px; }
.cell-label { fill: var(--text-muted); font-size: 11px; font-variant-numeric: tabular-nums; }

.cell-square { fill: transparent; cursor: pointer; }
.cell-square:hover { fill: var(--wash); }
.cell-square.selected { fill: var(--wash); }
.cell-label.selected { fill: var(--text-primary); font-weight: 600; }

.curve { fill: none; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }

.point { stroke: var(--surface-1); stroke-width: 2; }
.point.muted { fill: var(--text-muted); }
.point.active { fill: var(--text-primary); }

.hit { fill: transparent; cursor: pointer; }
.hit:focus { outline: none; }
.hit:focus-visible { stroke: var(--series-1); stroke-width: 2; }

.table-wrap { overflow-x: auto; margin-top: 12px; }

.results {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.85rem;
}

.results caption {
  text-align: left;
  color: var(--text-muted);
  font-size: 0.8rem;
  padding-bottom: 6px;
}

.results th,
.results td {
  text-align: left;
  padding: 6px 8px;
  border-bottom: 1px solid var(--grid);
  white-space: nowrap;
}

.results th { color: var(--text-secondary); font-weight: 600; }
.results .num { text-align: right; font-variant-numeric: tabular-nums; }
.results .eq { font-family: var(--mono); font-size: 0.8rem; white-space: normal; overflow-wrap: anywhere; }

/* Each model is a stacked block: name, equation, then three labelled values.
   The header row stays in the table for screen readers but is hidden visually. */
.results thead {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
}
.results tbody tr {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 2px 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--grid);
}
.results tbody th,
.results tbody td { border: 0; padding: 0; white-space: normal; }
.results tbody th[scope="row"],
.results tbody .eq { grid-column: 1 / -1; }
.results tbody .eq { margin-bottom: 4px; }
.results tbody td.num { text-align: left; }
.results tbody td.num::before {
  content: attr(data-label);
  display: block;
  color: var(--text-muted);
  font-size: 0.72rem;
}

.model-cell { display: flex; align-items: center; gap: 6px; }

.badge {
  font-size: 0.72rem;
  padding: 1px 6px;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--text-secondary);
}

.warn { color: var(--warning); }

.footnote { color: var(--text-secondary); font-size: 0.8rem; margin: 8px 0 0; }

.explainer { margin: 16px 0 40px; }
.explainer p, .explainer li { color: var(--text-secondary); max-width: 80ch; }
.explainer h2 { margin-bottom: 8px; }
.source { font-size: 0.9rem; }

.tooltip {
  position: fixed;
  z-index: 10;
  pointer-events: none;
  background: var(--surface-1);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 4px 16px rgba(0, 0, 0, 0.12);
  padding: 8px 10px;
  font-size: 0.8rem;
  font-variant-numeric: tabular-nums;
  max-width: 280px;
}

.tooltip .tt-title { font-weight: 600; margin-bottom: 2px; }
.tooltip .tt-row { display: flex; align-items: center; gap: 6px; color: var(--text-secondary); }
.tooltip .tt-row span:last-child { margin-left: auto; padding-left: 12px; color: var(--text-primary); }