:root {
  --ink: oklch(96% 0.025 210);
  --muted: oklch(70% 0.055 246);
  --night: oklch(16% 0.055 278);
  --deep-night: oklch(10% 0.04 278);
  --panel: oklch(21% 0.075 274);
  --panel-2: oklch(26% 0.085 271);
  --cyan: oklch(84% 0.16 194);
  --cyan-dark: oklch(57% 0.14 205);
  --magenta: oklch(70% 0.24 340);
  --magenta-dark: oklch(45% 0.18 337);
  --acid: oklch(89% 0.19 111);
  --danger: oklch(72% 0.22 28);
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --pixel-shadow: 4px 4px 0 oklch(7% 0.035 278);
  font-family: "Silkscreen", "Avenir Next", sans-serif;
  color: var(--ink);
  background: var(--deep-night);
  font-synthesis: none;
}

* {
  box-sizing: border-box;
  -webkit-tap-highlight-color: transparent;
}

html,
body {
  width: 100%;
  height: 100%;
  margin: 0;
  overflow: hidden;
  overscroll-behavior: none;
}

body {
  min-height: 100dvh;
  background:
    linear-gradient(180deg, oklch(13% 0.08 280 / 0.96), oklch(9% 0.035 278 / 0.98)),
    var(--deep-night);
  touch-action: manipulation;
}

button {
  font: inherit;
}

button:focus-visible {
  outline: 3px solid var(--cyan);
  outline-offset: 3px;
}

.city-backdrop,
.city-backdrop::before,
.city-backdrop::after {
  position: fixed;
  inset: 0;
  pointer-events: none;
}

.city-backdrop {
  overflow: hidden;
  z-index: 0;
}

.city-backdrop::before {
  content: "";
  z-index: 0;
  background:
    radial-gradient(ellipse at 50% 103%, oklch(55% 0.18 334 / 0.22) 0, transparent 48%),
    radial-gradient(circle at 84% 17%, oklch(76% 0.16 202 / 0.08) 0, transparent 18%),
    linear-gradient(180deg, transparent 58%, oklch(24% 0.1 284 / 0.22));
}

.city-backdrop::after {
  content: "";
  z-index: 8;
  opacity: 0.09;
  background: repeating-linear-gradient(0deg, transparent 0 3px, var(--cyan) 4px);
}

.stars {
  position: absolute;
  z-index: 1;
  width: 2px;
  height: 2px;
  background: oklch(80% 0.1 205);
}

.stars--far {
  top: 8%;
  left: 7%;
  opacity: 0.55;
  box-shadow: 9vw 19vh 0 oklch(76% 0.09 230), 19vw 5vh 0 oklch(70% 0.11 315), 28vw 27vh 0 oklch(76% 0.09 230), 39vw 3vh 0 oklch(79% 0.1 210), 47vw 17vh 0 oklch(69% 0.12 334), 57vw 31vh 0 oklch(80% 0.11 205), 69vw 7vh 0 oklch(77% 0.1 225), 78vw 26vh 0 oklch(72% 0.11 326), 87vw 3vh 0 oklch(80% 0.1 205), 92vw 36vh 0 oklch(76% 0.09 230), 13vw 41vh 0 oklch(69% 0.12 334), 34vw 45vh 0 oklch(80% 0.1 205), 64vw 43vh 0 oklch(76% 0.09 230), 83vw 49vh 0 oklch(80% 0.1 205), 4vw 56vh 0 oklch(76% 0.09 230), 23vw 62vh 0 oklch(80% 0.1 205), 44vw 55vh 0 oklch(70% 0.11 315), 58vw 68vh 0 oklch(76% 0.09 230), 73vw 59vh 0 oklch(80% 0.1 205), 89vw 72vh 0 oklch(69% 0.12 334), 16vw 78vh 0 oklch(77% 0.1 225), 37vw 83vh 0 oklch(76% 0.09 230), 67vw 88vh 0 oklch(80% 0.1 205), 95vw 91vh 0 oklch(76% 0.09 230);
}

.stars--near {
  top: 14%;
  left: 10%;
  width: 3px;
  height: 3px;
  box-shadow: 18vw 6vh 0 var(--magenta), 38vw -3vh 0 var(--cyan), 62vw 9vh 0 var(--cyan), 78vw 1vh 0 var(--cyan), 84vw 19vh 0 var(--magenta), 29vw 21vh 0 var(--cyan), 55vw 27vh 0 var(--cyan), 7vw 31vh 0 var(--cyan), 71vw 34vh 0 var(--cyan), 12vw 48vh 0 var(--magenta), 41vw 52vh 0 var(--cyan), 81vw 46vh 0 var(--cyan), 24vw 69vh 0 var(--cyan), 61vw 73vh 0 var(--magenta), 88vw 65vh 0 var(--cyan), 48vw 84vh 0 var(--cyan), 76vw 89vh 0 var(--cyan);
  animation: flicker 3s steps(2, end) infinite;
}

.pixel-moon {
  position: absolute;
  top: clamp(70px, 10vh, 110px);
  right: clamp(20px, 7vw, 90px);
  z-index: 1;
  width: clamp(58px, 10vw, 92px);
  aspect-ratio: 1;
  opacity: 0.58;
  clip-path: polygon(25% 0, 75% 0, 75% 7%, 88% 7%, 88% 18%, 100% 18%, 100% 75%, 92% 75%, 92% 88%, 75% 88%, 75% 100%, 25% 100%, 25% 94%, 12% 94%, 12% 82%, 0 82%, 0 25%, 7% 25%, 7% 12%, 25% 12%);
  background:
    linear-gradient(90deg, transparent 0 57%, oklch(44% 0.13 278 / 0.55) 57% 68%, transparent 68%) 0 20% / 100% 12% no-repeat,
    linear-gradient(90deg, oklch(47% 0.13 280 / 0.5) 0 22%, transparent 22%) 0 67% / 100% 14% no-repeat,
    oklch(80% 0.13 202);
  box-shadow: 0 0 0 4px oklch(64% 0.13 207 / 0.18);
}

.air-lanes {
  position: absolute;
  inset: 18% 0 auto;
  z-index: 2;
  height: 26%;
  overflow: hidden;
  opacity: 0.34;
}

.air-lanes i {
  position: absolute;
  width: 18vw;
  max-width: 180px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--magenta));
}

.air-lanes i::after {
  content: "";
  position: absolute;
  right: 0;
  top: -1px;
  width: 6px;
  height: 3px;
  background: var(--cyan);
  box-shadow: -4px 0 0 var(--magenta);
}

.air-lanes i:nth-child(1) { top: 8%; left: 15%; }
.air-lanes i:nth-child(2) { top: 52%; right: 10%; transform: scaleX(-1); }
.air-lanes i:nth-child(3) { top: 85%; left: 52%; width: 10vw; }

@media (max-height: 600px) {
  .pixel-moon {
    top: 54px;
    width: 52px;
  }
}

#app {
  position: relative;
  z-index: 2;
}

.app-shell {
  width: 100%;
  height: 100dvh;
  padding: max(var(--space-sm), env(safe-area-inset-top)) max(var(--space-sm), env(safe-area-inset-right)) max(var(--space-sm), env(safe-area-inset-bottom)) max(var(--space-sm), env(safe-area-inset-left));
  display: grid;
  grid-template-rows: 48px minmax(0, 1fr);
  gap: var(--space-sm);
}

.app-shell.is-locked {
  pointer-events: none;
}

.topbar {
  position: relative;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-inline: var(--space-xs);
}

.brand {
  display: grid;
  grid-template-columns: auto auto;
  grid-template-rows: auto auto;
  align-items: center;
  column-gap: var(--space-sm);
}

.brand__mark {
  grid-row: 1 / 3;
  width: 30px;
  height: 30px;
  display: flex;
  align-items: end;
  gap: 3px;
  border-bottom: 3px solid var(--magenta);
}

.brand__mark i {
  width: 7px;
  background: var(--cyan);
  box-shadow: 2px -2px 0 var(--magenta-dark);
}

.brand__mark i:nth-child(1) { height: 13px; }
.brand__mark i:nth-child(2) { height: 24px; }
.brand__mark i:nth-child(3) { height: 18px; }

.brand__name {
  color: var(--cyan);
  font-size: 1.25rem;
  line-height: 1;
  letter-spacing: 0.04em;
  text-shadow: 2px 2px 0 var(--magenta-dark);
}

.brand__sector {
  color: var(--muted);
  font-family: "Avenir Next", sans-serif;
  font-size: 0.58rem;
  letter-spacing: 0.16em;
}

.menu-trigger {
  width: 44px;
  height: 44px;
  display: grid;
  place-content: center;
  gap: 4px;
  border: 2px solid var(--cyan-dark);
  border-radius: 0;
  color: var(--cyan);
  background: var(--panel);
  box-shadow: 3px 3px 0 var(--magenta-dark);
}

.menu-trigger span {
  width: 20px;
  height: 3px;
  background: currentColor;
}

.menu-panel {
  position: absolute;
  top: 46px;
  right: 0;
  width: min(330px, calc(100vw - 16px));
  max-height: calc(100dvh - 62px);
  padding: var(--space-lg);
  display: grid;
  gap: var(--space-md);
  overflow: hidden;
  border: 3px solid var(--cyan);
  background: var(--night);
  box-shadow: 7px 7px 0 var(--magenta-dark);
  clip-path: polygon(0 0, calc(100% - 10px) 0, 100% 10px, 100% 100%, 10px 100%, 0 calc(100% - 10px));
}

.panel-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  color: var(--cyan);
  font-size: 1.05rem;
  letter-spacing: 0.08em;
}

.panel-heading button {
  width: 36px;
  height: 36px;
  border: 0;
  color: var(--cyan);
  background: transparent;
  font-size: 1.6rem;
}

.panel-action,
.size-switch button,
.error-screen button,
.level-clear button {
  min-height: 44px;
  border: 2px solid var(--cyan-dark);
  border-radius: 0;
  color: var(--ink);
  background: var(--panel-2);
  box-shadow: 3px 3px 0 var(--deep-night);
  letter-spacing: 0.05em;
}

.panel-action--hot,
.level-clear button {
  border-color: var(--magenta);
  color: var(--night);
  background: var(--magenta);
}

.size-switch {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-sm);
}

.size-switch button.is-active {
  border-color: var(--cyan);
  color: var(--night);
  background: var(--cyan);
}

.rules-panel p {
  margin: 0;
  color: var(--ink);
  font-family: "Avenir Next", sans-serif;
  font-size: 0.9rem;
  line-height: 1.45;
}

.rules-panel {
  overflow-y: auto;
  overscroll-behavior: contain;
}

.rules-section {
  display: grid;
  gap: var(--space-xs);
}

.rules-section h2 {
  margin: 0;
  color: var(--magenta);
  font-size: 0.72rem;
  letter-spacing: 0.07em;
}

.rules-section ul {
  margin: 0;
  padding-left: 1.25rem;
  display: grid;
  gap: var(--space-xs);
  color: var(--ink);
  font-family: "Avenir Next", sans-serif;
  font-size: 0.86rem;
  line-height: 1.4;
}

.rules-section li::marker {
  color: var(--cyan);
}

.game-shell {
  min-height: 0;
  display: grid;
  grid-template-areas: "board" "utility" "palette";
  grid-template-rows: minmax(0, 1fr) auto auto;
  gap: var(--space-sm);
  justify-items: center;
}

.board-stage {
  grid-area: board;
  width: 100%;
  min-height: 0;
  display: grid;
  place-items: center;
}

.board-frame {
  position: relative;
  width: min(94vw, calc(100dvh - 190px));
  max-width: 100%;
  max-height: 100%;
  aspect-ratio: 1;
  filter: drop-shadow(-5px 8px 0 oklch(7% 0.035 278 / 0.72));
  transform-style: preserve-3d;
}

.puzzle-grid {
  position: absolute;
  inset: 0;
  display: grid;
  grid-template-columns: 0.55fr repeat(var(--n), 1fr) 0.55fr;
  grid-template-rows: 0.55fr repeat(var(--n), 1fr) 0.55fr;
}

.puzzle-grid {
  padding: 2px;
  background: oklch(19% 0.08 274);
  border: 3px solid var(--cyan-dark);
  box-shadow:
    0 0 0 4px var(--panel),
    -6px 6px 0 4px var(--magenta-dark),
    -12px 12px 0 4px var(--panel),
    -14px 14px 0 4px var(--cyan-dark),
    0 0 24px oklch(70% 0.24 340 / 0.28);
  overflow: hidden;
}

.puzzle-grid::before,
.puzzle-grid::after {
  display: none;
}

.clue {
  --clue-fill: var(--panel-2);
  --clue-edge-inset: 2px;
  --clue-board-gap: clamp(4px, 1.2vw, 6px);
  position: relative;
  isolation: isolate;
  display: grid;
  place-items: center;
  z-index: 4;
  margin: var(--clue-edge-inset);
  border: 0;
  color: var(--cyan);
  background: var(--cyan-dark);
  font-size: clamp(0.85rem, 4.2vw, 1.45rem);
  line-height: 1;
  text-shadow: 2px 2px 0 var(--magenta-dark);
  filter: drop-shadow(-2px 2px 0 var(--magenta-dark));
  transition: color 120ms steps(2, end), background 120ms steps(2, end);
}

.clue--top {
  margin-bottom: var(--clue-board-gap);
  clip-path: polygon(0 0, 100% 0, 100% 72%, 62% 72%, 50% 100%, 38% 72%, 0 72%);
}

.clue--right {
  margin-left: var(--clue-board-gap);
  clip-path: polygon(28% 0, 100% 0, 100% 100%, 28% 100%, 28% 62%, 0 50%, 28% 38%);
}

.clue--bottom {
  margin-top: var(--clue-board-gap);
  clip-path: polygon(38% 28%, 50% 0, 62% 28%, 100% 28%, 100% 100%, 0 100%, 0 28%);
}

.clue--left {
  margin-right: var(--clue-board-gap);
  clip-path: polygon(0 0, 72% 0, 72% 38%, 100% 50%, 72% 62%, 72% 100%, 0 100%);
}

.clue::before {
  content: "";
  position: absolute;
  inset: 1px;
  z-index: -1;
  background: var(--clue-fill);
  clip-path: inherit;
}

.clue span {
  position: relative;
  z-index: 1;
  display: grid;
  place-items: center;
  width: 100%;
  height: 100%;
}

.clue--top span { padding-bottom: 18%; }
.clue--right span { padding-left: 18%; }
.clue--bottom span { padding-top: 18%; }
.clue--left span { padding-right: 18%; }

.clue.is-error {
  --clue-fill: var(--danger);
  color: var(--night);
  text-shadow: none;
}

.clue.is-error,
.grid-cell.is-error {
  animation: error-pulse 720ms steps(2, end) infinite;
}

.grid-cell {
  position: relative;
  z-index: 1;
  min-width: 0;
  min-height: 0;
  display: grid;
  place-items: center;
  padding: 0;
  border: 1px solid var(--cyan-dark);
  border-radius: 0;
  color: var(--ink);
  background: oklch(22% 0.07 274 / 0.98);
  overflow: hidden;
}

.grid-cell::after {
  display: none;
}

.grid-cell.is-filled {
  background: oklch(27% 0.09 274 / 0.98);
}

.grid-cell.is-selected {
  z-index: 2;
  color: var(--ink);
  background: oklch(22% 0.07 274 / 0.98);
}

.grid-cell.is-selected.is-filled {
  background: oklch(27% 0.09 274 / 0.98);
}

.grid-cell.is-error {
  color: var(--night);
  background: var(--danger);
  box-shadow: inset 0 0 0 3px oklch(44% 0.19 22);
}

.cell-grid {
  position: absolute;
  inset: 0;
  opacity: 0.2;
  background:
    linear-gradient(90deg, transparent 48%, var(--cyan) 49% 51%, transparent 52%),
    linear-gradient(0deg, transparent 48%, var(--cyan) 49% 51%, transparent 52%);
}

.iso-tower-slot {
  position: relative;
  z-index: 5;
  pointer-events: none;
}

.iso-tower-slot.is-selected::after {
  content: "";
  position: absolute;
  inset: 0;
  z-index: 10;
  border: 3px solid var(--acid);
  pointer-events: none;
}

.iso-tower {
  --depth-unit: clamp(4px, 1.35vw, 7px);
  --center-unit: clamp(2px, 0.675vw, 3.5px);
  --depth: calc(var(--tower) * var(--depth-unit));
  --center-offset: calc(var(--tower) * var(--center-unit));
  position: absolute;
  top: calc(16% - var(--center-offset));
  left: calc(16% + var(--center-offset));
  width: 68%;
  height: 68%;
  color: var(--cyan);
  pointer-events: none;
}

.size-5 .iso-tower {
  --depth-unit: clamp(4px, 1vw, 6px);
  --center-unit: clamp(2px, 0.5vw, 3px);
  top: calc(17% - var(--center-offset));
  left: calc(17% + var(--center-offset));
  width: 66%;
  height: 66%;
}

.iso-tower__roof,
.iso-tower__front,
.iso-tower__side {
  position: absolute;
  display: block;
}

.iso-tower__roof {
  inset: 0;
  display: grid;
  place-items: center;
  color: var(--night);
  background: var(--cyan);
  z-index: 3;
}

.iso-tower__front {
  top: 100%;
  left: calc(var(--depth) * -1);
  z-index: 2;
  width: calc(100% + var(--depth));
  height: var(--depth);
  background: var(--cyan-dark);
  clip-path: polygon(var(--depth) 0, 100% 0, calc(100% - var(--depth)) 100%, 0 100%);
}

.iso-tower__side {
  top: 0;
  left: calc(var(--depth) * -1);
  z-index: 1;
  width: var(--depth);
  height: calc(100% + var(--depth));
  background: oklch(40% 0.12 214);
  clip-path: polygon(100% 0, 100% calc(100% - var(--depth)), 0 100%, 0 var(--depth));
}

.cell-value {
  position: relative;
  z-index: 1;
  font-size: clamp(0.82rem, 4vw, 1.35rem);
  line-height: 1;
  text-shadow: none;
}

.grid-cell:disabled + .iso-tower-slot .iso-tower {
  animation: iso-tower-rise 520ms cubic-bezier(0.16, 1, 0.3, 1) both;
  animation-delay: var(--delay);
}

.iso-tower-slot.is-selected .cell-value,
.iso-tower-slot.is-error .cell-value {
  text-shadow: none;
}

.utility-rail,
.number-rail {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.utility-rail { grid-area: utility; }
.number-rail { grid-area: palette; }

.control,
.number-key {
  min-width: 48px;
  height: 48px;
  border: 2px solid var(--cyan-dark);
  border-radius: 0;
  color: var(--cyan);
  background: var(--panel);
  box-shadow: 3px 3px 0 var(--deep-night);
}

.control {
  display: grid;
  place-items: center;
  padding-inline: 9px;
  text-align: center;
}

.control__label {
  font-family: "Avenir Next", sans-serif;
  font-size: 0.64rem;
  text-transform: uppercase;
}

.control:disabled,
.number-key:disabled {
  opacity: 0.32;
  box-shadow: none;
}

.rail-label {
  color: var(--muted);
  font-family: "Avenir Next", sans-serif;
  font-size: 0.58rem;
  letter-spacing: 0.16em;
  writing-mode: vertical-rl;
  transform: rotate(180deg);
}

.number-keys {
  display: flex;
  gap: var(--space-sm);
}

.number-key {
  font-size: 1.55rem;
}

.number-key.is-active {
  border-color: var(--acid);
  color: var(--night);
  background: var(--acid);
}

.number-key--erase {
  border-color: var(--magenta-dark);
  color: var(--magenta);
}

.board-frame.is-turning-right {
  animation: turn-right 460ms cubic-bezier(0.16, 1, 0.3, 1) both;
}

.board-frame.is-turning-left {
  animation: turn-left 460ms cubic-bezier(0.16, 1, 0.3, 1) both;
}

.is-turning-right .turn-content { animation: counter-right 460ms cubic-bezier(0.16, 1, 0.3, 1) both; }
.is-turning-left .turn-content { animation: counter-left 460ms cubic-bezier(0.16, 1, 0.3, 1) both; }

.celebration {
  position: absolute;
  inset: 0;
  z-index: 10;
  overflow: hidden;
  pointer-events: auto;
}

.level-clear {
  position: absolute;
  inset: 0;
  z-index: 3;
  display: grid;
  place-content: center;
  gap: var(--space-sm);
  padding: var(--space-xl);
  text-align: center;
  background: oklch(10% 0.055 278 / 0.82);
  opacity: 0;
  animation: clear-arrive 350ms steps(4, end) 1.05s forwards;
}

.level-clear__eyebrow {
  color: var(--cyan);
  font-size: 0.78rem;
  letter-spacing: 0.18em;
}

.level-clear strong {
  color: var(--cyan);
  font-size: clamp(2.5rem, 14vw, 5.5rem);
  line-height: 0.77;
  text-shadow: 5px 5px 0 var(--magenta);
}

.level-clear button {
  margin-top: var(--space-md);
  padding-inline: var(--space-xl);
}

.app-shell.app-shell--message {
  display: grid;
  grid-template-rows: minmax(0, 1fr);
  place-items: center;
}

.boot-screen,
.status-screen,
.error-screen {
  max-width: min(520px, 92vw);
  display: grid;
  justify-items: start;
  gap: var(--space-md);
  padding: var(--space-xl);
  border: 3px solid var(--cyan-dark);
  background: var(--night);
  box-shadow: 8px 8px 0 var(--magenta-dark);
}

.boot-screen__signal,
.error-screen__code {
  color: var(--cyan);
  font-size: 0.72rem;
  letter-spacing: 0.17em;
}

.boot-screen h1,
.error-screen h1 {
  margin: 0;
  color: var(--cyan);
  font-size: clamp(2.4rem, 12vw, 5rem);
  line-height: 0.82;
  text-shadow: 5px 5px 0 var(--magenta-dark);
}

.boot-screen p,
.error-screen p {
  margin: 0;
  color: var(--muted);
  font-family: "Avenir Next", sans-serif;
}

.status-screen {
  place-items: center;
  color: var(--cyan);
}

.status-screen__pixels {
  width: 52px;
  height: 12px;
  background: repeating-linear-gradient(90deg, var(--magenta) 0 8px, transparent 8px 12px);
  animation: loading 640ms steps(4, end) infinite;
}

.status-screen small {
  color: var(--muted);
  letter-spacing: 0.18em;
}

.error-screen div {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-md);
}

.error-screen button {
  padding-inline: var(--space-lg);
}

@keyframes flicker { 50% { opacity: 0.35; } }
@keyframes error-pulse { 50% { background: var(--magenta); } }
@keyframes loading { 50% { transform: translateX(8px); } }
@keyframes turn-right { 45% { transform: rotateX(10deg) rotateZ(47deg) scale(0.9); } 100% { transform: rotateX(0) rotateZ(90deg) scale(1); } }
@keyframes turn-left { 45% { transform: rotateX(-10deg) rotateZ(-47deg) scale(0.9); } 100% { transform: rotateX(0) rotateZ(-90deg) scale(1); } }
@keyframes counter-right { to { transform: rotateZ(-90deg); } }
@keyframes counter-left { to { transform: rotateZ(90deg); } }
@keyframes iso-tower-rise {
  from {
    opacity: 0.25;
    transform: translate(calc(var(--depth) * -1), var(--depth));
  }
  to {
    opacity: 1;
    transform: translate(0, 0);
  }
}
@keyframes clear-arrive { to { opacity: 1; } }

@media (orientation: landscape) and (max-height: 520px) {
  .app-shell {
    grid-template-rows: 40px minmax(0, 1fr);
    gap: var(--space-xs);
    padding-top: max(var(--space-xs), env(safe-area-inset-top));
    padding-bottom: max(var(--space-xs), env(safe-area-inset-bottom));
  }

  .error-screen {
    gap: var(--space-sm);
    padding: var(--space-md);
  }

  .error-screen h1 {
    font-size: clamp(2rem, 12vh, 3.5rem);
  }

  .brand__mark { width: 25px; height: 25px; }
  .brand__name { font-size: 1.05rem; }
  .brand__sector { display: none; }
  .menu-trigger { width: 38px; height: 38px; }
  .menu-panel { top: 39px; width: 300px; max-height: calc(100dvh - 48px); padding: var(--space-md); gap: var(--space-sm); }
  .panel-action, .size-switch button { min-height: 40px; }

  .game-shell {
    width: 100%;
    grid-template-areas: "utility board palette";
    grid-template-columns: 120px minmax(0, 1fr) 142px;
    grid-template-rows: minmax(0, 1fr);
    gap: var(--space-md);
    justify-items: stretch;
  }

  .board-frame {
    width: auto;
    height: 100%;
    max-width: 100%;
  }

  .utility-rail,
  .number-rail {
    height: 100%;
    display: grid;
    align-content: center;
    gap: var(--space-sm);
  }

  .utility-rail { grid-template-columns: repeat(2, 52px); }
  .number-rail { grid-template-columns: 10px 1fr; }
  .number-keys { display: grid; grid-template-columns: repeat(2, 52px); gap: var(--space-sm); }
  .control, .number-key { width: 52px; min-width: 52px; height: 52px; }
  .control { padding: 0 4px; }
  .rail-label { justify-self: center; }
  .clue { font-size: clamp(0.75rem, 3.2vh, 1.2rem); }
  .cell-value { font-size: clamp(0.72rem, 3.2vh, 1rem); }
  .level-clear strong { font-size: clamp(2.4rem, 15vh, 4.5rem); }
}

@media (min-width: 900px) and (min-height: 600px) {
  .app-shell { max-width: 1120px; margin-inline: auto; padding-inline: var(--space-xl); }
  .game-shell {
    grid-template-areas: "utility board palette";
    grid-template-columns: 170px minmax(0, 1fr) 170px;
    grid-template-rows: minmax(0, 1fr);
    gap: var(--space-xl);
  }
  .board-frame { width: min(64dvh, 100%); }
  .utility-rail, .number-rail { height: 100%; flex-direction: column; }
  .number-keys { display: grid; grid-template-columns: repeat(2, 56px); }
  .rail-label { writing-mode: horizontal-tb; transform: none; }
  .control { min-width: 130px; }
}