:root {
  color-scheme: light dark;
  --bg: #f4f1e8;
  --surface: #fffdf7;
  --surface-strong: #ffffff;
  --field-bg: #ffffff;
  --panel-muted: #f7f4ec;
  --grid-cell-bg: #fffefa;
  --on-accent: #ffffff;
  --ink: #111111;
  --muted: #5d5d57;
  --border: #20201d;
  --border-soft: #d8d2c3;
  --accent: #0b6b57;
  --accent-strong: #084c3f;
  --danger: #b42318;
  --warning: #b35c00;
  --success-bg: #dff3e8;
  --error-bg: #ffe1dd;
  --strong-border: #a15c00;
  --strong-bg: #fff3d7;
  --strong-ink: #6f3d00;
  --preview-mask-bg: rgb(255 253 247 / 72%);
  --backdrop: rgb(17 17 17 / 38%);
  --shadow: 0 16px 45px rgb(28 25 20 / 12%);
  --popover-shadow: 0 10px 28px rgb(28 25 20 / 14%);
  --modal-shadow: 0 24px 80px rgb(0 0 0 / 24%);
  --drawer-shadow: -18px 0 45px rgb(28 25 20 / 18%);
  font-family:
    Inter,
    ui-sans-serif,
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --surface: #1c1c1a;
    --surface-strong: #252522;
    --field-bg: #10100f;
    --panel-muted: #23231f;
    --grid-cell-bg: #181816;
    --on-accent: #ffffff;
    --ink: #f4f1e8;
    --muted: #aaa49a;
    --border: #e5dece;
    --border-soft: #454137;
    --accent: #45b894;
    --accent-strong: #83d9bb;
    --danger: #ff766d;
    --warning: #ffb35c;
    --success-bg: #143628;
    --error-bg: #421e1a;
    --strong-border: #ffb35c;
    --strong-bg: #3a2a13;
    --strong-ink: #ffd28e;
    --preview-mask-bg: rgb(28 28 26 / 72%);
    --backdrop: rgb(0 0 0 / 58%);
    --shadow: 0 16px 45px rgb(0 0 0 / 34%);
    --popover-shadow: 0 10px 28px rgb(0 0 0 / 36%);
    --modal-shadow: 0 24px 80px rgb(0 0 0 / 55%);
    --drawer-shadow: -18px 0 45px rgb(0 0 0 / 38%);
  }
}

* {
  box-sizing: border-box;
}

body {
  min-height: 100vh;
  margin: 0;
  background: var(--bg);
  color: var(--ink);
}

button,
input {
  font: inherit;
}

button {
  cursor: pointer;
  touch-action: manipulation;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.56;
}

.app-shell {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 28px 0 32px;
}

.about-section {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 4px 0 22px;
  color: var(--muted);
}

.about-section-inner {
  max-width: 760px;
}

.about-section h2 {
  margin: 0 0 8px;
  color: var(--ink);
  font-size: 18px;
  line-height: 1.25;
  letter-spacing: 0;
}

.about-section p {
  max-width: 72ch;
  margin: 0 0 8px;
  font-size: 13px;
  line-height: 1.55;
}

.notice-section {
  width: min(1180px, calc(100vw - 32px));
  margin: 0 auto;
  padding: 0 0 24px;
  color: var(--muted);
}

.notice-section-inner {
  max-width: 820px;
  border-top: 1px solid var(--border-soft);
  padding-top: 14px;
}

.notice-section h2 {
  margin: 0 0 8px;
  color: var(--ink);
  font-size: 16px;
  line-height: 1.3;
  letter-spacing: 0;
}

.notice-section p {
  max-width: 78ch;
  margin: 0 0 8px;
  font-size: 12px;
  line-height: 1.55;
}

.topbar {
  display: flex;
  align-items: end;
  justify-content: space-between;
  gap: 24px;
  margin-bottom: 18px;
}

h1,
h2,
p {
  margin: 0;
}

h1 {
  font-size: 34px;
  line-height: 1.1;
  letter-spacing: 0;
}

.topbar p {
  margin-top: 6px;
  color: var(--muted);
  font-size: 15px;
}

.title-block {
  flex: 1 1 auto;
  min-width: 0;
}

.title-line {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-width: 0;
}

.language-picker {
  position: relative;
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
}

.title-controls {
  display: inline-flex;
  flex: 0 0 auto;
  align-items: center;
  justify-content: flex-end;
  gap: 4px;
}

.language-options {
  position: absolute;
  z-index: 12;
  top: calc(100% + 8px);
  right: 0;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 4px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--popover-shadow);
}

.language-options[hidden] {
  display: none;
}

.language-choice {
  display: inline-grid;
  width: 42px;
  height: 38px;
  place-items: center;
  border: 1px solid var(--border-soft);
  border-radius: 7px;
  background: var(--surface-strong);
  color: var(--ink);
  font-size: 13px;
  font-weight: 850;
}

.language-choice[aria-checked="true"] {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--on-accent);
}

.language-toggle {
  width: 42px;
  min-width: 42px;
  height: 42px;
  min-height: 42px;
}

.settings-button,
.settings-panel-header,
.settings-backdrop {
  display: none;
}

.primary-button,
.ghost-button,
.icon-button {
  min-height: 42px;
  border-radius: 8px;
  padding: 0 18px;
  border: 1.5px solid var(--border);
  font-weight: 750;
  transition:
    transform 120ms ease,
    background-color 160ms ease,
    color 160ms ease;
}

.primary-button {
  background: var(--ink);
  color: var(--bg);
}

.ghost-button {
  background: var(--surface);
  color: var(--ink);
}

.icon-button {
  position: relative;
  display: inline-grid;
  place-items: center;
  width: 46px;
  min-width: 46px;
  height: 46px;
  min-height: 46px;
  border: 0;
  padding: 0;
  background: transparent;
  color: var(--ink);
}

.settings-button {
  display: none;
}

.music-button[aria-pressed="false"] {
  color: var(--muted);
  opacity: 0.68;
}

.music-button[aria-pressed="false"] svg {
  color: var(--ink);
}

.music-button[aria-pressed="false"]::after {
  position: absolute;
  width: 22px;
  height: 22px;
  border: 2px solid var(--danger);
  border-radius: 999px;
  color: var(--danger);
  content: "";
}

.music-button[aria-pressed="false"]::before {
  position: absolute;
  z-index: 1;
  width: 18px;
  height: 2px;
  border-radius: 999px;
  background: var(--danger);
  content: "";
  transform: rotate(-30deg);
}

.icon-button svg {
  width: 22px;
  height: 22px;
  fill: none;
  stroke: currentColor;
  stroke-linecap: round;
  stroke-linejoin: round;
  stroke-width: 2.2;
}

.primary-button:hover,
.ghost-button:hover,
.icon-button:hover {
  transform: translateY(-1px);
}

.primary-button:active,
.ghost-button:active,
.icon-button:active {
  transform: translateY(0) scale(0.98);
}

.status-strip {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 10px;
  align-items: center;
  margin-bottom: 12px;
}

.status-item {
  min-height: 30px;
  color: var(--muted);
}

.status-item strong {
  display: block;
  font-size: 22px;
  font-weight: 850;
  line-height: 1;
}

.status-item:nth-child(2) {
  text-align: center;
}

.status-item:nth-child(3) {
  text-align: right;
}

.error-item strong {
  color: var(--danger);
}

.error-item strong[hidden] {
  display: none;
}

.timer-item.warning strong {
  color: var(--warning);
}

.timer-item.danger strong {
  color: var(--danger);
}

.game-layout {
  display: grid;
  grid-template-columns: 290px minmax(0, 1fr);
  gap: 18px;
  align-items: start;
}

.control-panel,
.play-surface {
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  background: var(--surface);
  box-shadow: var(--shadow);
}

.control-panel {
  padding: 18px;
}

.settings-panel-header {
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 18px;
}

.settings-panel-header strong {
  font-size: 22px;
  line-height: 1.1;
}

.control-group + .control-group,
.seconds-field,
.checkbox-field,
.benchmark-box {
  margin-top: 18px;
}

.control-label,
.seconds-field span,
.benchmark-title {
  display: block;
  margin-bottom: 8px;
  color: var(--muted);
  font-size: 13px;
  font-weight: 800;
  text-transform: uppercase;
}

.segmented {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 8px;
}

.difficulty-control {
  grid-template-columns: 1fr;
}

.segmented button {
  min-height: 40px;
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  background: var(--surface-strong);
  color: var(--ink);
  font-weight: 750;
}

.segmented button[aria-checked="true"] {
  border-color: var(--accent);
  background: var(--accent);
  color: var(--on-accent);
}

.seconds-field input {
  width: 100%;
  min-height: 44px;
  border: 1.5px solid var(--border);
  border-radius: 8px;
  padding: 0 12px;
  background: var(--field-bg);
  color: var(--ink);
  font-weight: 750;
}

.checkbox-field {
  display: flex;
  align-items: center;
  gap: 10px;
  color: var(--ink);
  font-size: 14px;
  font-weight: 750;
  line-height: 1.35;
}

.checkbox-field input {
  width: 18px;
  height: 18px;
  accent-color: var(--accent);
  flex: 0 0 auto;
}

.benchmark-box {
  padding: 14px;
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  background: var(--panel-muted);
}

.benchmark-box dl,
.result-stats {
  margin: 0;
}

.benchmark-box div,
.result-stats div {
  display: flex;
  justify-content: space-between;
  gap: 16px;
}

.benchmark-box div + div,
.result-stats div + div {
  margin-top: 8px;
}

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

dd {
  margin: 0;
  font-weight: 800;
}

.play-surface {
  padding: 20px;
}

.grid-wrap {
  position: relative;
  width: min(100%, 680px);
  margin: 0 auto;
  aspect-ratio: 1;
}

.grid-board {
  display: grid;
  width: 100%;
  height: 100%;
  border: 2px solid var(--border);
  background: var(--border);
  gap: 2px;
  touch-action: manipulation;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.grid-cell {
  position: relative;
  border: 0;
  border-radius: 0;
  background: var(--grid-cell-bg);
  color: var(--ink);
  font-size: clamp(20px, 5vw, 44px);
  font-weight: 850;
  letter-spacing: 0;
  line-height: 1;
  transition:
    background-color 130ms ease,
    color 130ms ease,
    transform 120ms ease,
    opacity 160ms ease;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
}

.grid-cell.tap-feedback {
  background: var(--success-bg);
  box-shadow: inset 0 0 0 4px var(--accent);
  color: var(--accent-strong);
  transform: scale(0.98);
}

.grid-cell.tutorial-target.tap-feedback {
  animation: none;
}

.grid-cell.tutorial-target {
  z-index: 1;
  animation: tutorial-flash 900ms ease-in-out infinite;
}

.grid-cell.tutorial-target::after {
  position: absolute;
  z-index: 2;
  bottom: -18px;
  left: 50%;
  color: var(--accent);
  content: "☝";
  font-size: 22px;
  line-height: 1;
  pointer-events: none;
  transform-origin: 50% 100%;
  animation: tutorial-tap 900ms ease-in-out infinite;
}

@keyframes tutorial-flash {
  0%,
  100% {
    background: var(--grid-cell-bg);
    color: var(--ink);
  }

  50% {
    background: var(--success-bg);
    color: var(--accent-strong);
  }
}

@keyframes tutorial-tap {
  0%,
  100% {
    opacity: 0.95;
    transform: translate(-50%, 2px) scale(1);
  }

  45% {
    opacity: 1;
    transform: translate(-50%, -2px) scale(0.86);
  }

  70% {
    opacity: 0.82;
    transform: translate(-50%, 1px) scale(1.04);
  }
}

.confetti-layer {
  position: fixed;
  z-index: 1000;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
}

.confetti-layer i {
  position: absolute;
  top: 0;
  left: var(--confetti-x);
  width: 8px;
  height: 14px;
  border-radius: 2px;
  background: var(--confetti-color);
  opacity: 0;
  transform: translate3d(-50%, 0, 0) rotate(0deg);
  animation: confetti-fall var(--confetti-duration) ease-out
    var(--confetti-delay) forwards;
}

.confetti-layer i:nth-child(3n) {
  width: 10px;
  height: 10px;
  border-radius: 999px;
}

.confetti-layer i:nth-child(4n) {
  width: 6px;
  height: 16px;
}

@keyframes confetti-fall {
  0% {
    opacity: 0;
    transform: translate3d(-50%, -8px, 0) rotate(0deg);
  }

  12% {
    opacity: 0.95;
  }

  100% {
    opacity: 0;
    transform: translate3d(
        calc(-50% + var(--confetti-drift)),
        var(--confetti-fall),
        0
      )
      rotate(var(--confetti-spin));
  }
}

.pause-mask {
  position: absolute;
  inset: 0;
  display: grid;
  place-content: center;
  gap: 10px;
  border: 2px solid var(--border);
  background: var(--surface);
  text-align: center;
}

.pause-mask.preview-mask {
  border: 2px solid var(--border);
  background: var(--preview-mask-bg);
  pointer-events: none;
}

.pause-mask.preview-mask strong,
.pause-mask.preview-mask span {
  justify-self: center;
}

.pause-mask.preview-mask strong {
  font-size: 40px;
  line-height: 1;
}

.pause-mask.preview-mask span {
  font-weight: 800;
}

.tutorial-mode {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 6px;
  margin-top: 8px;
}

.tutorial-mode[hidden] {
  display: none;
}

.tutorial-mode-label {
  width: max-content;
  padding: 4px 10px;
  border: 1px solid var(--border-soft);
  border-radius: 999px;
  background: var(--panel-muted);
  color: var(--muted);
  font-size: 12px;
  font-weight: 850;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.tutorial-start-button {
  min-height: 28px;
  border: 0;
  border-radius: 999px;
  padding: 4px 10px;
  background: var(--panel-muted);
  color: var(--accent);
  font-size: 12px;
  font-weight: 850;
}

.tutorial-start-button:hover {
  color: var(--accent-strong);
}

.tutorial-start-button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.pause-mask[hidden] {
  display: none;
}

.pause-mask strong {
  font-size: 30px;
}

.pause-mask span {
  color: var(--muted);
}

.mask-help {
  width: min(320px, calc(100% - 48px));
  justify-self: center;
  font-size: 13px;
  line-height: 1.45;
}

.mask-actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
}

.mask-actions[hidden] {
  display: none;
}

.tutorial-dismiss-button {
  min-height: 34px;
  padding: 0 12px;
}

.tutorial-dismiss-button {
  border-color: var(--border-soft);
  color: var(--muted);
  font-size: 13px;
}

.result-dialog {
  width: min(460px, calc(100vw - 32px));
  border: 2px solid var(--border);
  border-radius: 8px;
  padding: 0;
  color: var(--ink);
  background: var(--surface);
  box-shadow: var(--modal-shadow);
}

.result-dialog.result-strong {
  border-color: var(--strong-border);
}

.result-dialog.result-expert {
  border-color: var(--accent);
}

.result-dialog::backdrop {
  background: var(--backdrop);
}

.dialog-body {
  position: relative;
  padding: 22px;
}

.result-close-button {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 38px;
  min-width: 38px;
  height: 38px;
  min-height: 38px;
  border: 0;
  background: transparent;
}

.result-close-button svg {
  width: 26px;
  height: 26px;
}

.dialog-body h2 {
  padding-right: 40px;
  font-size: 28px;
  line-height: 1.15;
}

.dialog-body p {
  margin-top: 8px;
  color: var(--muted);
}

.result-badge {
  margin-top: 16px;
  padding: 12px 14px;
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  font-weight: 850;
}

.result-badge[hidden] {
  display: none;
}

.result-strong .result-badge {
  border-color: var(--strong-border);
  background: var(--strong-bg);
  color: var(--strong-ink);
}

.result-expert .result-badge {
  border-color: var(--accent);
  background: var(--success-bg);
  color: var(--accent-strong);
}

.result-stats {
  margin-top: 18px;
  padding: 14px;
  border: 1px solid var(--border-soft);
  border-radius: 8px;
  background: var(--panel-muted);
}

.site-footer {
  display: flex;
  width: min(1180px, calc(100vw - 32px));
  align-items: center;
  justify-content: center;
  gap: 8px;
  margin: 0 auto;
  padding: 0 0 24px;
  color: var(--muted);
  font-size: 12px;
  font-weight: 750;
}

.site-footer img {
  width: 18px;
  height: 18px;
}

.project-link,
.github-link {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  color: inherit;
  text-decoration: none;
}

.project-link:hover,
.github-link:hover {
  color: var(--text);
}

.project-link:focus-visible,
.github-link:focus-visible {
  border-radius: 4px;
  outline: 2px solid var(--accent);
  outline-offset: 3px;
}

.github-link svg {
  width: 16px;
  height: 16px;
  fill: currentColor;
}

@media (max-width: 820px) {
  body.settings-open {
    overflow: hidden;
  }

  .app-shell {
    width: min(100vw - 20px, 680px);
    padding-top: 16px;
  }

  .site-footer {
    width: min(100vw - 20px, 680px);
    flex-wrap: wrap;
    gap: 6px;
    padding-bottom: 16px;
    font-size: 11px;
  }

  body.game-focus-scroll .app-shell {
    padding-bottom: max(65dvh, 460px);
  }

  .topbar {
    align-items: stretch;
    flex-direction: column;
  }

  .settings-button {
    display: inline-grid;
  }

  .status-strip {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }

  .game-layout {
    display: block;
  }

  .control-panel {
    position: fixed;
    z-index: 30;
    top: 0;
    right: 0;
    width: min(340px, calc(100vw - 42px));
    height: 100dvh;
    padding: 18px;
    overflow-y: auto;
    border-top: 0;
    border-right: 0;
    border-bottom: 0;
    border-radius: 8px 0 0 8px;
    box-shadow: var(--drawer-shadow);
    transform: translateX(100%);
    transition: transform 220ms cubic-bezier(0.16, 1, 0.3, 1);
  }

  body.settings-open .control-panel {
    transform: translateX(0);
  }

  .settings-panel-header {
    display: flex;
  }

  .settings-backdrop {
    position: fixed;
    z-index: 20;
    inset: 0;
    display: block;
    background: var(--backdrop);
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease;
  }

  body.settings-open .settings-backdrop {
    opacity: 1;
    pointer-events: auto;
  }

  .settings-backdrop[hidden] {
    display: none;
  }

  .play-surface {
    padding: 12px;
  }

  .grid-cell {
    font-size: clamp(18px, 7vw, 32px);
  }
}

@media (orientation: landscape) and (max-height: 500px) and (max-width: 950px) {
  body.settings-open {
    overflow: hidden;
  }

  .app-shell {
    display: grid;
    grid-template-columns: minmax(90px, 1fr) auto minmax(48px, 1fr);
    column-gap: 10px;
    align-items: start;
    width: min(100vw - 20px, 900px);
    padding: 8px 0 12px;
  }

  body.game-focus-scroll .app-shell {
    padding-bottom: 12px;
  }

  .topbar {
    display: contents;
  }

  .title-block,
  .title-line {
    display: contents;
  }

  h1 {
    grid-column: 1;
    grid-row: 1;
    align-self: center;
    font-size: 24px;
    line-height: 1;
  }

  .topbar p {
    display: none;
  }

  .title-controls {
    grid-column: 3;
    grid-row: 1;
    align-self: center;
    justify-self: end;
    flex-direction: column;
  }

  .language-toggle,
  .icon-button {
    width: 38px;
    min-width: 38px;
    height: 38px;
    min-height: 38px;
  }

  .language-options {
    top: 0;
    right: calc(100% + 6px);
  }

  .settings-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }

  .game-layout {
    grid-column: 2;
    grid-row: 1;
    align-self: start;
    display: block;
  }

  .control-panel {
    position: fixed;
    z-index: 30;
    top: 0;
    right: 0;
    width: min(340px, calc(100vw - 42px));
    height: 100dvh;
    padding: 18px;
    overflow-y: auto;
    border-top: 0;
    border-right: 0;
    border-bottom: 0;
    border-radius: 8px 0 0 8px;
    box-shadow: var(--drawer-shadow);
    transform: translateX(100%);
    transition: transform 220ms cubic-bezier(0.16, 1, 0.3, 1);
  }

  body.settings-open .control-panel {
    transform: translateX(0);
  }

  .settings-panel-header {
    display: flex;
  }

  .settings-backdrop {
    position: fixed;
    z-index: 20;
    inset: 0;
    display: block;
    background: var(--backdrop);
    opacity: 0;
    pointer-events: none;
    transition: opacity 180ms ease;
  }

  body.settings-open .settings-backdrop {
    opacity: 1;
    pointer-events: auto;
  }

  .settings-backdrop[hidden] {
    display: none;
  }

  .play-surface {
    width: min(calc(100dvh - 20px), calc(100vw - 220px), 420px);
    margin: 0 auto;
    padding: 8px;
  }

  .grid-wrap {
    width: min(100%, calc(100dvh - 106px));
  }

  .tutorial-mode {
    gap: 4px;
    margin-top: 4px;
  }

  .status-strip {
    margin-bottom: 6px;
  }

  .status-item {
    min-height: 22px;
  }

  .status-item strong {
    font-size: 18px;
  }

  .grid-cell {
    font-size: clamp(16px, 6dvh, 28px);
  }

  .site-footer {
    grid-column: 1 / -1;
    width: min(100vw - 20px, 900px);
    padding: 0 0 8px;
    font-size: 10px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 1ms !important;
    scroll-behavior: auto !important;
    transition-duration: 1ms !important;
  }
}