:root {
  color-scheme: light;

  --accent: #4f46e5;
  --on-accent: #ffffff;
  --bg: #f4f5fb;
  --surface: #ffffff;
  --cell-bg: #eef0f8;
  --cell-hover: #e3e6f4;
  --text: #1c1e2e;
  --muted: #666b85;
  --tile-back: #4f46e5;
  --tile-back-2: #7c75f0;
  --match-bg: #d7f5e3;
  --wrong-bg: #fde0e8;
  --focus: #0ea5e9;

  --font-mark: 'Fredoka', ui-rounded, 'Arial Rounded MT Bold', system-ui, sans-serif;

  --gap: 0.6rem;
  --radius: 1rem;
  --board-max: 28rem;
  --shadow: 0 0.5rem 1.5rem rgb(30 32 60 / 0.12);
  --ease: cubic-bezier(0.2, 0.8, 0.2, 1);
}

:root[data-theme='dark'] {
  color-scheme: dark;
  --accent: #8b8cff;
  --on-accent: #12132a;
  --bg: #0f1020;
  --surface: #1a1c33;
  --cell-bg: #25284a;
  --cell-hover: #2f3360;
  --text: #eceefb;
  --muted: #9aa0c4;
  --tile-back: #5a5cd6;
  --tile-back-2: #8b8cff;
  --match-bg: #14452f;
  --wrong-bg: #5a2238;
  --shadow: 0 0.5rem 1.5rem rgb(0 0 0 / 0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme]) {
    color-scheme: dark;
    --accent: #8b8cff;
    --on-accent: #12132a;
    --bg: #0f1020;
    --surface: #1a1c33;
    --cell-bg: #25284a;
    --cell-hover: #2f3360;
    --text: #eceefb;
    --muted: #9aa0c4;
    --tile-back: #5a5cd6;
    --tile-back-2: #8b8cff;
    --match-bg: #14452f;
    --wrong-bg: #5a2238;
    --shadow: 0 0.5rem 1.5rem rgb(0 0 0 / 0.4);
  }
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  display: grid;
  place-items: center;
  padding: max(1rem, env(safe-area-inset-top)) 1rem max(1rem, env(safe-area-inset-bottom));
  background: var(--bg);
  color: var(--text);
  font-family: system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
  -webkit-tap-highlight-color: transparent;
  transition: background-color 0.25s var(--ease), color 0.25s var(--ease);
}

.app {
  width: 100%;
  max-width: var(--board-max);
  display: grid;
  gap: 1rem;
  padding: 1rem;
  background: var(--surface);
  border-radius: calc(var(--radius) * 1.5);
  box-shadow: var(--shadow);
}

h1 {
  margin: 0;
  font-size: clamp(1.25rem, 5vw, 1.75rem);
  text-align: center;
  letter-spacing: 0.02em;
}

.app-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.app-header h1 {
  flex: 1;
  text-align: center;
}

/* Balances the toggle so the title stays centred. */
.app-header::before {
  content: '';
  flex: none;
  width: 2.75rem;
}

.theme-toggle {
  flex: none;
  display: grid;
  place-items: center;
  width: 2.75rem;
  height: 2.75rem;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: var(--cell-bg);
  color: var(--text);
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 0.15s var(--ease), background-color 0.2s var(--ease);
}

.theme-toggle:active { transform: scale(0.9); }

@media (hover: hover) and (pointer: fine) {
  .theme-toggle:hover { background: var(--cell-hover); }
}

/* ---------- Levels ---------- */

.levels {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
}

.level {
  min-height: 2.75rem;
  padding: 0 0.5rem;
  border: 0;
  border-radius: 0.75rem;
  background: var(--cell-bg);
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 700;
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 0.15s var(--ease), background-color 0.2s var(--ease);
}

.level[aria-pressed='true'] {
  background: var(--accent);
  color: var(--on-accent);
}

.level:active { transform: scale(0.96); }

@media (hover: hover) and (pointer: fine) {
  .level[aria-pressed='false']:hover { background: var(--cell-hover); }
}

/* ---------- Scoreboard ---------- */

.scoreboard {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 0.5rem;
  margin: 0;
  text-align: center;
}

.scoreboard div {
  padding: 0.4rem;
  border-radius: 0.6rem;
  background: var(--cell-bg);
}

.scoreboard dt {
  font-size: 0.75rem;
  color: var(--muted);
}

.scoreboard dd {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.status {
  margin: 0;
  min-height: 1.5em;
  text-align: center;
  font-weight: 600;
  font-size: 1.1rem;
}

/* ---------- Board ---------- */

.board {
  display: grid;
  grid-template-columns: repeat(var(--cols, 3), minmax(0, 1fr));
  gap: var(--gap);
  width: 100%;
}

.board[data-locked] { pointer-events: none; }

.tile {
  appearance: none;
  position: relative;
  aspect-ratio: 1 / 1;
  min-width: 0;
  padding: 0;
  border: 0;
  background: none;
  color: var(--text);
  font: inherit;
  cursor: pointer;
  perspective: 600px;
  touch-action: manipulation;
  -webkit-user-select: none;
  user-select: none;
  transition: transform 0.15s var(--ease);
}

.tile:disabled { cursor: default; }
.tile:active:not(:disabled) { transform: scale(0.94); }

.tile:focus-visible,
.reset:focus-visible,
.level:focus-visible,
.theme-toggle:focus-visible {
  outline: 3px solid var(--focus);
  outline-offset: 2px;
}

.tile__inner {
  position: absolute;
  inset: 0;
  transform-style: preserve-3d;
  transition: transform 0.4s var(--ease);
}

.tile[data-state='open'] .tile__inner,
.tile[data-state='matched'] .tile__inner {
  transform: rotateY(180deg);
}

.tile__face {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: var(--radius);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
}

.tile__face--front {
  background: linear-gradient(135deg, var(--tile-back), var(--tile-back-2));
}

.tile__face--back {
  transform: rotateY(180deg);
  background: var(--cell-bg);
  font-size: clamp(1.75rem, 11vw, 3rem);
  line-height: 1;
}

.tile[data-state='matched'] .tile__face--back {
  background: var(--match-bg);
  animation: pop 0.4s var(--ease);
}

.tile.is-wrong .tile__face--back {
  background: var(--wrong-bg);
  animation: shake 0.4s var(--ease);
}

@media (hover: hover) and (pointer: fine) {
  .tile[data-state='closed']:hover { transform: translateY(-2px); }
}

/* ---------- Buttons ---------- */

.actions {
  display: grid;
}

.reset {
  padding: 0.85rem 1rem;
  min-height: 2.75rem;
  border: 0;
  border-radius: var(--radius);
  background: var(--accent);
  color: var(--on-accent);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 0.15s var(--ease), filter 0.2s var(--ease);
}

@media (hover: hover) and (pointer: fine) {
  .reset:hover { filter: brightness(1.1); }
}

.reset:active { transform: scale(0.97); }

/* ---------- Win dialog ---------- */

.dialog {
  max-width: min(22rem, calc(100vw - 2rem));
  padding: 0;
  border: 0;
  border-radius: calc(var(--radius) * 1.5);
  background: var(--surface);
  color: var(--text);
  box-shadow: var(--shadow);
  overflow: visible;
}

.dialog::backdrop { background: rgb(15 16 32 / 0.55); }

.dialog__card {
  display: grid;
  justify-items: center;
  gap: 0.75rem;
  padding: 1.5rem;
  text-align: center;
}

.dialog__card .reset { width: 100%; }

.dialog__badge {
  font-size: 4rem;
  line-height: 1;
  animation: bounce 1s var(--ease) infinite;
}

.dialog__title {
  margin: 0;
  font-family: var(--font-mark);
  font-size: 1.6rem;
}

.dialog__summary {
  margin: 0;
  color: var(--muted);
}

/* ---------- Confetti ---------- */

.confetti {
  position: fixed;
  inset: 0;
  pointer-events: none;
  overflow: hidden;
  z-index: 10;
}

.confetti__piece {
  position: absolute;
  top: -1rem;
  width: 0.6rem;
  height: 1rem;
  border-radius: 2px;
  animation: confetti-fall var(--dur, 2.5s) cubic-bezier(0.3, 0.6, 0.5, 1) var(--delay, 0s) forwards;
}

@keyframes confetti-fall {
  to {
    transform: translate3d(var(--drift, 0), 110vh, 0) rotate(var(--spin, 720deg));
    opacity: 0.9;
  }
}

@keyframes pop {
  50% { transform: rotateY(180deg) scale(1.12); }
}

@keyframes shake {
  0%, 100% { transform: rotateY(180deg) translateX(0); }
  25%      { transform: rotateY(180deg) translateX(-6px); }
  75%      { transform: rotateY(180deg) translateX(6px); }
}

@keyframes bounce {
  50% { transform: translateY(-0.5rem) rotate(6deg); }
}

@media (max-width: 360px) {
  :root { --gap: 0.4rem; --radius: 0.75rem; }
  .app { padding: 0.75rem; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation: none !important;
    transition: none !important;
  }
}