:root {
  --bg: #f4f1ea;
  --panel: #fffdf9;
  --line: #d9d2c3;
  --text: #22252b;
  --muted: #646158;
  --accent: #2f4f74;
  --button: #ebe6da;
  --button-hover: #ded7c7;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #12161c;
    --panel: #1a2029;
    --line: #2f3946;
    --text: #e8ebef;
    --muted: #a3acb8;
    --accent: #e0b456;
    --button: #232b36;
    --button-hover: #2e3845;
    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;
}

#plane {
  display: block;
  width: 100%;
  aspect-ratio: 4 / 3;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: #10161f;
  touch-action: none;
}

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

.stage-bar {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  align-items: center;
  gap: 8px;
  margin-top: 8px;
}

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

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

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

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

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='range'],
.row select {
  grid-column: 1 / -1;
  width: 100%;
}

output {
  font-variant-numeric: tabular-nums;
  color: var(--muted);
}

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

select {
  padding: 4px 6px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
}

.buttons {
  display: flex;
  gap: 6px;
}

.buttons.wrap {
  flex-wrap: wrap;
}

button {
  padding: 6px 12px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--button);
  cursor: pointer;
}

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

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

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

.check {
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: 10px;
}

.counts {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 2px 12px;
  margin: 0;
  font-variant-numeric: tabular-nums;
}

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

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

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