* { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  min-height: 100%;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  color: #fff;
  -webkit-font-smoothing: antialiased;
}

.app {
  max-width: 560px;
  margin: 0 auto;
  padding: 24px 16px 40px;
}

header { text-align: center; margin-bottom: 20px; }
header h1 { font-size: 2rem; letter-spacing: -0.5px; }
.sub { opacity: 0.8; margin-top: 4px; font-size: 0.95rem; }

.stats {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
  margin-bottom: 20px;
}
.stat {
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(8px);
  border-radius: 12px;
  padding: 10px 8px;
  text-align: center;
}
.stat .label {
  display: block;
  font-size: 0.75rem;
  opacity: 0.8;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 4px;
}
.stat span:last-child {
  font-size: 1.3rem;
  font-weight: 600;
  font-variant-numeric: tabular-nums;
}

.board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  margin-bottom: 20px;
}

.card {
  aspect-ratio: 1;
  perspective: 1000px;
  cursor: pointer;
}
.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.5s cubic-bezier(.4,.2,.2,1);
  transform-style: preserve-3d;
}
.card.flipped .card-inner,
.card.matched .card-inner {
  transform: rotateY(180deg);
}
.card-front, .card-back {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 12px;
  backface-visibility: hidden;
  font-size: clamp(2rem, 8vw, 2.8rem);
  user-select: none;
}
.card-front {
  background: linear-gradient(135deg, #f093fb 0%, #f5576c 100%);
  color: #fff;
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}
.card-front::after {
  content: "?";
  font-weight: 700;
  font-size: 2rem;
}
.card-back {
  background: #fff;
  color: #333;
  transform: rotateY(180deg);
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}
.card.matched .card-back {
  background: linear-gradient(135deg, #43e97b 0%, #38f9d7 100%);
  animation: pop 0.4s ease;
}
@keyframes pop {
  0% { transform: rotateY(180deg) scale(1); }
  50% { transform: rotateY(180deg) scale(1.1); }
  100% { transform: rotateY(180deg) scale(1); }
}

.controls { text-align: center; }
.btn {
  background: #fff;
  color: #764ba2;
  border: none;
  padding: 12px 28px;
  border-radius: 999px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.15s, box-shadow 0.15s;
  box-shadow: 0 4px 12px rgba(0,0,0,0.15);
}
.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 18px rgba(0,0,0,0.25); }
.btn:active { transform: translateY(0); }

.win {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.6);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 20px;
  animation: fadeIn 0.3s ease;
}
.win.hidden { display: none; }
.win-card {
  background: #fff;
  color: #333;
  padding: 32px 40px;
  border-radius: 20px;
  text-align: center;
  max-width: 360px;
  width: 100%;
  animation: slideUp 0.4s cubic-bezier(.2,.8,.2,1);
}
.win-card h2 { font-size: 2rem; margin-bottom: 16px; color: #764ba2; }
.win-card p { margin: 6px 0; font-size: 1.1rem; }
.win-card .btn { margin-top: 20px; }

@keyframes fadeIn { from { opacity: 0; } to { opacity: 1; } }
@keyframes slideUp { from { opacity: 0; transform: translateY(30px); } to { opacity: 1; transform: translateY(0); } }

@media (max-width: 400px) {
  .board { gap: 8px; }
  header h1 { font-size: 1.6rem; }
}