:root {
  --bg: #f4f1ea;
  --panel: #fffdf9;
  --line: #d9d2c3;
  --text: #22252b;
  --muted: #605d55;
  --accent: #b23a0b;
  --span: #c2410c;
  --largest: #1e3a5f;
  --hist: #c9c1b0;
  --button: #ebe6da;
  --button-hover: #ded7c7;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121418;
    --panel: #1b1e24;
    --line: #2f343d;
    --text: #e8e9ec;
    --muted: #a5a9b2;
    --accent: #fb923c;
    --span: #fb923c;
    --largest: #93c5fd;
    --hist: #3a404b;
    --button: #252a32;
    --button-hover: #30363f;
    color-scheme: dark;
  }
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.5 system-ui, -apple-system, 'Segoe UI', sans-serif;
}

header,
footer {
  max-width: 1200px;
  margin: 0 auto;
  padding: 16px;
}

h1 {
  margin: 8px 0 4px;
  font-size: 1.8rem;
  letter-spacing: 0.02em;
}

.subtitle,
footer {
  color: var(--muted);
  max-width: 72ch;
}

footer {
  font-size: 0.85rem;
}

a {
  color: var(--accent);
}

main {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 16px;
  display: grid;
  grid-template-columns: minmax(0, 1fr) 300px;
  gap: 16px;
  align-items: start;
}

@media (max-width: 860px) {
  main {
    grid-template-columns: minmax(0, 1fr);
  }
}

.stage {
  min-width: 0;
}

#grid {
  display: block;
  width: 100%;
  max-width: 760px;
  aspect-ratio: 1;
  margin: 0 auto;
  border-radius: 6px;
  border: 1px solid var(--line);
  image-rendering: pixelated;
  cursor: crosshair;
  touch-action: none;
}

#grid:focus-visible {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.p-bar {
  max-width: 760px;
  margin: 12px auto 0;
  display: grid;
  gap: 4px;
}

.p-bar label {
  font-weight: 600;
}

.p-bar output {
  font-variant-numeric: tabular-nums;
  color: var(--accent);
  margin-left: 4px;
}

.p-bar input {
  width: 100%;
}

.stage-bar {
  max-width: 760px;
  margin: 8px auto 0;
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
}

.status {
  margin: 0;
  color: var(--muted);
  font-variant-numeric: tabular-nums;
}

.hint,
.note {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 6px auto 0;
  max-width: 760px;
}

.controls {
  display: grid;
  gap: 12px;
}

fieldset {
  margin: 0;
  padding: 10px 12px 12px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: var(--panel);
  min-width: 0;
}

legend {
  padding: 0 4px;
  font-weight: 600;
}

.choice {
  display: grid;
  gap: 2px;
  margin-bottom: 6px;
}

.row {
  display: grid;
  grid-template-columns: 1fr auto;
  align-items: center;
  gap: 4px 8px;
  margin-top: 6px;
}

.row input[type='number'] {
  width: 9em;
}

select,
input,
button {
  font: inherit;
  color: inherit;
}

select,
input[type='number'] {
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 4px;
  padding: 2px 4px;
}

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

.buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.stage-bar .buttons {
  margin-top: 0;
}

button {
  background: var(--button);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 4px 10px;
  cursor: pointer;
}

button:hover:not(:disabled) {
  background: var(--button-hover);
}

button:disabled {
  opacity: 0.5;
  cursor: default;
}

button:focus-visible,
select:focus-visible,
input:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.stats {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 2px 8px;
  margin: 0;
  font-variant-numeric: tabular-nums;
}

.stats dt {
  color: var(--muted);
}

.stats dd {
  margin: 0;
  text-align: right;
}

.chart {
  margin: 10px 0 0;
}

.chart svg {
  display: block;
  width: 100%;
  height: auto;
}

.chart .axis {
  stroke: var(--line);
  stroke-width: 1;
}

.chart .tick {
  fill: var(--muted);
  font-size: 9px;
}

.chart .curve {
  fill: none;
  stroke-width: 2;
}

.chart .curve.span {
  stroke: var(--span);
}

.chart .curve.largest {
  stroke: var(--largest);
  stroke-dasharray: 4 3;
}

.chart .hist {
  fill: var(--hist);
}

.chart .marker {
  stroke: var(--text);
  stroke-width: 1;
  opacity: 0.6;
}

.chart .pc {
  stroke: var(--muted);
  stroke-width: 1;
  stroke-dasharray: 2 2;
}

figcaption {
  display: flex;
  flex-wrap: wrap;
  gap: 4px 10px;
  font-size: 0.8rem;
  color: var(--muted);
}

.key::before {
  content: '';
  display: inline-block;
  width: 14px;
  height: 3px;
  margin-right: 4px;
  vertical-align: middle;
}

.key.span::before {
  background: var(--span);
}

.key.largest::before {
  background: repeating-linear-gradient(90deg, var(--largest) 0 4px, transparent 4px 7px);
}

.key.hist::before {
  height: 8px;
  background: var(--hist);
}

kbd {
  font: 0.8rem ui-monospace, monospace;
  padding: 0 4px;
  border: 1px solid var(--line);
  border-radius: 3px;
  background: var(--panel);
}

.chart .points circle {
  fill: var(--span);
}

.chart path.pc {
  fill: none;
}

.key.dot::before {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--span);
}

.key.ref::before {
  height: 0;
  border-top: 1px dashed var(--muted);
}