/* ── Reset & base ─────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
  --bg:        #f0f4f8;
  --surface:   #ffffff;
  --surface2:  #e8edf3;
  --border:    #cdd5e0;
  --text:      #1a202c;
  --text-muted:#64748b;
  --accent:    #6366f1;
  --accent-h:  #4f46e5;
  --card-back: #6366f1;
  --card-front:#dde4f0;
  --card-matched: #10b981;
  --shadow:    0 2px 8px rgba(0,0,0,.10);
  --shadow-lg: 0 8px 24px rgba(0,0,0,.14);
  --radius:    12px;
  --transition: .2s ease;
}

:root.dark {
  --bg:        #0f172a;
  --surface:   #1e293b;
  --surface2:  #293548;
  --border:    #334155;
  --text:      #f1f5f9;
  --text-muted:#94a3b8;
  --card-back: #4f46e5;
  --card-front:#1e293b;
  --card-matched: #059669;
}

html { font-size: 16px; }

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100dvh;
  transition: background var(--transition), color var(--transition);
}

/* ── Confetti canvas ─────────────────────────────────────────── */
#confetti-canvas {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 100;
  display: none;
}

/* ── Win overlay ─────────────────────────────────────────────── */
.win-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.55);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  animation: fadeIn .3s ease;
}
.win-overlay[hidden] { display: none; }

.win-box {
  background: var(--surface);
  border-radius: var(--radius);
  padding: 2.5rem 3rem;
  text-align: center;
  box-shadow: var(--shadow-lg);
  max-width: 340px;
  width: 90%;
}
.win-box h2 { font-size: 1.8rem; margin-bottom: .75rem; }
.win-box p  { color: var(--text-muted); margin-bottom: 1.5rem; font-size: 1rem; }
.win-box button {
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: .7rem 2rem;
  font-size: 1rem;
  cursor: pointer;
  transition: background var(--transition);
}
.win-box button:hover { background: var(--accent-h); }

/* ── App layout ──────────────────────────────────────────────── */
.app {
  max-width: 960px;
  margin: 0 auto;
  padding: 1rem 1rem 3rem;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

/* ── Header ──────────────────────────────────────────────────── */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: .5rem;
}
.header-title h1 { font-size: 1.6rem; line-height: 1.1; }
.subtitle { font-size: .85rem; color: var(--text-muted); }
.header-controls { display: flex; gap: .5rem; }

.icon-btn {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: .4rem .9rem;
  font-size: .82rem;
  cursor: pointer;
  color: var(--text);
  transition: background var(--transition), border-color var(--transition);
  white-space: nowrap;
}
.icon-btn:hover { background: var(--surface2); border-color: var(--accent); }

/* ── Controls bar ────────────────────────────────────────────── */
.controls {
  display: flex;
  gap: .75rem;
  align-items: flex-end;
  flex-wrap: wrap;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: .75rem 1rem;
  box-shadow: var(--shadow);
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: .25rem;
}
.control-group label {
  font-size: .75rem;
  font-weight: 600;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: .05em;
}
.control-group select {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: .4rem .7rem;
  font-size: .9rem;
  color: var(--text);
  cursor: pointer;
  transition: border-color var(--transition);
  min-width: 140px;
}
.control-group select:focus { outline: none; border-color: var(--accent); }

.reset-btn {
  margin-left: auto;
  background: var(--accent);
  color: #fff;
  border: none;
  border-radius: 8px;
  padding: .5rem 1.25rem;
  font-size: .95rem;
  font-weight: 600;
  cursor: pointer;
  transition: background var(--transition), transform .1s;
  white-space: nowrap;
}
.reset-btn:hover  { background: var(--accent-h); }
.reset-btn:active { transform: scale(.97); }

/* ── Stats bar ───────────────────────────────────────────────── */
.stats {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: .5rem;
}

.stat {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: .6rem .75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .15rem;
  box-shadow: var(--shadow);
}
.stat-label {
  font-size: .7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .06em;
  color: var(--text-muted);
}
.stat-value {
  font-size: 1.3rem;
  font-weight: 700;
  color: var(--accent);
  font-variant-numeric: tabular-nums;
}

/* ── Card grid ───────────────────────────────────────────────── */
.grid {
  display: grid;
  gap: clamp(4px, 1vw, 10px);
  width: 100%;
}

/* ── Card ────────────────────────────────────────────────────── */
.card {
  aspect-ratio: 3/4;
  cursor: pointer;
  perspective: 600px;
  outline: none;
  border-radius: var(--radius);
}

/* Keyboard focus ring */
.card:focus-visible .card-inner {
  outline: 3px solid var(--accent);
  outline-offset: 2px;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transform-style: preserve-3d;
  transition: transform .45s cubic-bezier(.4,0,.2,1);
  border-radius: var(--radius);
}

.card.flipped .card-inner,
.card.matched .card-inner {
  transform: rotateY(180deg);
}

.card-front,
.card-back {
  position: absolute;
  inset: 0;
  border-radius: var(--radius);
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: clamp(1.1rem, 3vw, 2rem);
  user-select: none;
  box-shadow: var(--shadow);
}

/* Back face (hidden) – shown initially */
.card-front {
  background: var(--card-front);
  background-image: repeating-linear-gradient(
    135deg,
    transparent 0 10px,
    rgba(255,255,255,.06) 10px 20px
  );
}

/* Front face (value) – shown when flipped */
.card-back {
  background: var(--card-back);
  color: #fff;
  transform: rotateY(180deg);
  font-weight: 700;
}

/* Matched cards */
.card.matched .card-back {
  background: var(--card-matched);
}

/* Shape SVG inside card-back */
.card-back svg {
  width: 60%;
  height: 60%;
  max-width: 52px;
  max-height: 52px;
}

/* Hiragana / alphabet sizing */
.card-back {
  font-size: clamp(1rem, 4vw, 2.2rem);
}

/* Hover animation (not on matched) */
.card:not(.matched):hover .card-inner {
  transform: translateY(-3px) scale(1.03);
  box-shadow: var(--shadow-lg);
}
.card.flipped:not(.matched):hover .card-inner {
  transform: rotateY(180deg) translateY(-3px) scale(1.03);
}

/* ── Animations ──────────────────────────────────────────────── */
@keyframes fadeIn {
  from { opacity: 0; transform: scale(.95); }
  to   { opacity: 1; transform: scale(1); }
}

/* ── Responsive ──────────────────────────────────────────────── */
@media (max-width: 600px) {
  .stats { grid-template-columns: repeat(2, 1fr); }
  .controls { gap: .5rem; }
  .control-group select { min-width: 120px; }
  .reset-btn { width: 100%; margin-left: 0; }
}

@media (max-width: 380px) {
  .header-title h1 { font-size: 1.3rem; }
  .icon-btn { padding: .35rem .6rem; font-size: .75rem; }
}