:root {
  --bg: #f2f7fb;
  --card: #2563eb;
  --card-2: #1e4fbe;
  --flip: #ffffff;
  --line: #dbe7f2;
  --ink: #123040;
  --muted: #5b7185;
}
* { box-sizing: border-box; }
body {
  margin: 0;
  padding: 10px 10px 26px;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
  touch-action: manipulation;
}
.topbar {
  display: flex;
  justify-content: center;
  gap: 12px;
  max-width: 720px;
  margin: 0 auto 8px;
}
.stat {
  flex: 1;
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 8px 6px;
  text-align: center;
}
.stat b { display: block; font-size: 1.15rem; font-variant-numeric: tabular-nums; }
.stat span { font-size: .72rem; text-transform: uppercase; letter-spacing: .06em; color: var(--muted); }
.controls {
  display: flex;
  align-items: center;
  justify-content: center;
  flex-wrap: wrap;
  gap: 8px;
  max-width: 720px;
  margin: 0 auto 10px;
  font-size: .9rem;
}
.controls select, .controls button {
  font: inherit;
  padding: 7px 12px;
  border-radius: 8px;
  border: 1px solid var(--line);
  background: #fff;
  color: var(--ink);
  cursor: pointer;
}
.controls button { background: var(--card); border-color: var(--card); color: #fff; font-weight: 600; }
.record { color: var(--muted); font-size: .82rem; }
.board {
  display: grid;
  gap: 8px;
  margin: 0 auto;
  width: min(92vw, calc(92vh - 190px), 720px);
  grid-template-columns: repeat(var(--cols, 4), 1fr);
}
.card {
  position: relative;
  aspect-ratio: 1;
  perspective: 600px;
  cursor: pointer;
}
.card-inner {
  position: absolute;
  inset: 0;
  border-radius: 12px;
  transform-style: preserve-3d;
  transition: transform .35s;
  box-shadow: 0 2px 8px rgba(18, 48, 64, .12);
}
.card.flipped .card-inner, .card.matched .card-inner { transform: rotateY(180deg); }
.card-face {
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  border-radius: 12px;
  backface-visibility: hidden;
  font-size: clamp(18px, 6vw, 40px);
}
.card-back {
  background: linear-gradient(145deg, var(--card), var(--card-2));
  color: rgba(255,255,255,.85);
  font-size: 1.1rem;
}
.card-front {
  background: var(--flip);
  border: 2px solid var(--line);
  transform: rotateY(180deg);
}
.card.matched .card-front { border-color: #8bc34a; box-shadow: 0 0 0 2px rgba(139,195,74,.35) inset; }
.card.matched { cursor: default; }
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(12, 30, 44, .55);
  display: grid;
  place-items: center;
  z-index: 50;
}
.overlay[hidden] { display: none; }
.overlay-box {
  background: #fff;
  border-radius: 16px;
  padding: 22px 26px;
  text-align: center;
  max-width: 340px;
  box-shadow: 0 20px 60px rgba(18, 48, 64, .3);
}
.overlay-box h2 { margin: 0 0 6px; }
.overlay-box p { margin: 0 0 16px; color: var(--muted); font-size: .95rem; }
.overlay-box button {
  font: inherit;
  padding: 10px 18px;
  border-radius: 10px;
  border: 0;
  background: var(--card);
  color: #fff;
  font-weight: 700;
  cursor: pointer;
}
@media (max-width: 480px) {
  .board { gap: 6px; }
  .stat b { font-size: 1rem; }
}