:root {
  color-scheme: dark;
  --page: #101310;
  --panel: #171b17;
  --panel-soft: #1d221d;
  --line: #394039;
  --line-strong: #707970;
  --text: #ecefe9;
  --muted: #a7afa6;
  --gold: #d2bd7c;
  --rust: #c17d69;
  --focus: #f0c27a;
}

* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  color: var(--text);
  background: var(--page);
  font-family: "Yu Gothic", "Hiragino Sans", "Meiryo", system-ui, sans-serif;
  line-height: 1.65;
}
a { color: inherit; text-underline-offset: 4px; }
button, input, select { font: inherit; }
button, select {
  min-height: 44px;
  border: 1px solid var(--line-strong);
  border-radius: 3px;
  background: var(--panel-soft);
  color: var(--text);
}
button { padding: 8px 12px; cursor: pointer; }
button:hover:not(:disabled) { border-color: var(--gold); }
button:disabled { cursor: not-allowed; opacity: .48; }
button:focus-visible, input:focus-visible, select:focus-visible, a:focus-visible, #lifeCanvas:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 3px;
}
.skip-link {
  position: absolute;
  top: .75rem;
  left: .75rem;
  z-index: 10;
  transform: translateY(-180%);
  padding: .65rem .9rem;
  border: 2px solid var(--focus);
  background: var(--panel);
}
.skip-link:focus-visible { transform: none; }
.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.shell { width: min(1280px, calc(100% - 36px)); margin: 0 auto; padding: 22px 0 38px; }
.page-header {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: 24px;
  align-items: start;
  padding: 2px 0 22px;
  border-bottom: 1px solid var(--line-strong);
}
.back-link { display: inline-flex; min-height: 44px; align-items: center; color: var(--muted); }
.eyebrow { margin: 0 0 5px; color: var(--rust); font-size: .78rem; }
h1, h2, p { margin-top: 0; }
h1, h2 { font-family: "Yu Mincho", "Hiragino Mincho ProN", "MS Mincho", serif; font-weight: 500; }
h1 { margin-bottom: 7px; font-size: clamp(2.2rem, 6vw, 3.7rem); line-height: 1.2; }
.lead { margin: 0; color: var(--muted); }
.playground { display: grid; grid-template-columns: minmax(0, 1.55fr) minmax(290px, .75fr); gap: 22px; align-items: start; padding-top: 22px; }
.board-column, .controls-column { min-width: 0; }
.board-head { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 8px; }
.board-head p { margin: 0; color: var(--muted); font-size: .9rem; }
.quiet-button { min-height: 38px; padding: 5px 9px; font-size: .82rem; }
.board-size-controls { min-width: 0; margin: 0; padding: 5px 10px 9px; border: 1px solid var(--line); }
.board-size-controls legend { padding: 0 5px; color: var(--muted); font-size: .84rem; }
.dimension-row { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr) auto; gap: 8px; align-items: end; }
.dimension-row > label { display: flex; align-items: center; justify-content: space-between; gap: 6px; min-width: 0; color: var(--muted); font-size: .88rem; }
.number-with-unit { display: flex; align-items: center; min-width: 0; border: 1px solid var(--line-strong); background: var(--page); color: var(--muted); }
.number-with-unit input { width: 68px; min-width: 0; min-height: 42px; padding: 4px 6px; border: 0; background: transparent; color: var(--text); font-variant-numeric: tabular-nums; }
.number-with-unit > span { padding-right: 6px; font-size: .8rem; }
.dimension-times { align-self: center; padding-bottom: 8px; color: var(--muted); }
.dimension-row > button { min-height: 42px; white-space: nowrap; }
#boardSizeHelp { margin: 5px 0 0; color: var(--muted); font-size: .76rem; }
.board-transport { display: grid; gap: 5px; margin: 9px 0 11px; }
.primary-actions { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 7px; }
.primary-actions button { min-width: 0; padding: 7px 6px; }
.speed-control { display: grid; grid-template-columns: auto auto minmax(0, 1fr); gap: 0 9px; align-items: center; margin: 0; color: var(--muted); font-size: .84rem; }
.speed-control input { grid-column: 1 / -1; width: 100%; min-height: 44px; margin: 0; accent-color: var(--gold); }
.board-tools-row { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 10px; align-items: center; margin-bottom: 8px; }
.segmented { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: 5px; }
.zoom-controls { display: grid; grid-template-columns: auto 54px auto auto; gap: 5px; align-items: center; }
.zoom-controls button { min-width: 52px; min-height: 44px; padding: 5px 8px; white-space: nowrap; }
.zoom-controls output { text-align: center; font-variant-numeric: tabular-nums; }
.board-frame { max-height: min(75vh, 760px); overflow: auto; overscroll-behavior: contain; border: 1px solid var(--line-strong); background: #0a100d; }
#lifeCanvas { display: block; width: 100%; max-width: none; aspect-ratio: var(--board-aspect, 21 / 13); touch-action: none; cursor: crosshair; }
#lifeCanvas.is-pan-mode { cursor: grab; }
.board-help { margin: 8px 0 14px; color: var(--muted); font-size: .84rem; }
.cursor-readout { margin: -8px 0 14px; color: var(--text); font-size: .84rem; font-variant-numeric: tabular-nums; }
.readout { display: flex; flex-wrap: wrap; gap: 8px 24px; padding: 11px 0; border-top: 1px solid var(--line); border-bottom: 1px solid var(--line); }
.readout p { margin: 0; color: var(--muted); font-size: .88rem; }
.readout strong { color: var(--text); font-variant-numeric: tabular-nums; }
.controls-column { display: grid; gap: 15px; }
.control-section { padding: 13px 14px 15px; border-top: 1px solid var(--line-strong); background: var(--panel); }
.control-section h2 { margin: 0 0 10px; font-size: 1.12rem; }
.control-section label { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin: 12px 0 5px; color: var(--muted); font-size: .88rem; }
.button-row { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 8px; }
.button-row > * { flex: 1 1 auto; min-width: 0; }
.primary-button { border-color: var(--gold); color: var(--gold); }
.mode-button.is-active { border-color: var(--gold); color: var(--gold); }
select { width: 100%; padding: 0 9px; }
input[type="range"] { width: 100%; min-height: 44px; accent-color: var(--gold); }
.button-row input[type="range"] { flex: 1 1 90px; }
.button-row select { flex: 1 1 145px; }
.button-row button { flex: 0 0 auto; }
output { color: var(--text); font-variant-numeric: tabular-nums; }
.check-row { justify-content: flex-start !important; min-height: 44px; margin-bottom: 0 !important; cursor: pointer; }
.check-row input { width: 20px; height: 20px; accent-color: var(--gold); }
.action-status { min-height: 1.6em; margin: 10px 0 0; color: var(--muted); font-size: .88rem; }
.page-footer { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 8px 18px; margin-top: 25px; padding-top: 15px; border-top: 1px solid var(--line); color: var(--muted); font-size: .85rem; }
.page-footer p { margin: 0; }
.page-footer a { color: var(--gold); }
@media (max-width: 850px) {
  .playground { grid-template-columns: minmax(0, 1fr); gap: 18px; }
  .controls-column { grid-template-columns: repeat(2, minmax(0, 1fr)); align-items: start; }
  .action-status { grid-column: 1 / -1; }
}
@media (max-width: 520px) {
  .shell { width: calc(100% - 24px); padding-top: 12px; }
  .page-header { grid-template-columns: 1fr; gap: 8px; padding-bottom: 16px; }
  h1 { font-size: clamp(2rem, 11vw, 2.7rem); }
  .playground { padding-top: 16px; }
  .controls-column { grid-template-columns: minmax(0, 1fr); gap: 12px; }
  .dimension-row { grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); gap: 6px; }
  .dimension-row > button { grid-column: 1 / -1; width: 100%; }
  .number-with-unit input { width: 62px; }
  .primary-actions { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .primary-actions button { min-height: 46px; }
  .board-tools-row { grid-template-columns: minmax(0, 1fr); gap: 6px; }
  .zoom-controls { grid-template-columns: auto minmax(54px, 1fr) auto auto; }
  .zoom-controls output { justify-self: end; }
  .readout { gap: 5px 16px; }
  .board-help { font-size: .78rem; }
}