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

body {
  font-family: 'Segoe UI', 'Arial Rounded MT Bold', Arial, sans-serif;
  background: linear-gradient(135deg, #e0f7fa 0%, #fff9c4 50%, #f8bbd0 100%);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: flex-start;
  padding: 16px;
}

.game-container {
  max-width: 600px;
  width: 100%;
  text-align: center;
}

h1 {
  font-size: 2.2rem;
  color: #1565c0;
  margin-bottom: 12px;
  text-shadow: 1px 1px 0 rgba(255, 255, 255, 0.7);
}

.status-bar {
  display: flex;
  justify-content: center;
  gap: 24px;
  margin-bottom: 16px;
  font-size: 1.1rem;
  color: #37474f;
}

.score strong {
  color: #e65100;
}

/* Grid */
.grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
}

/* Card */
.card {
  aspect-ratio: 1;
  perspective: 500px;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
}

.card-inner {
  position: relative;
  width: 100%;
  height: 100%;
  transition: transform 0.35s ease;
  transform-style: preserve-3d;
}

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

.card-front,
.card-back {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 14px;
  backface-visibility: hidden;
  font-weight: 700;
}

.card-front {
  background: linear-gradient(145deg, #42a5f5, #1e88e5);
  color: #fff;
  font-size: 2rem;
  box-shadow: 0 4px 12px rgba(25, 118, 210, 0.3);
}

.card-front::after {
  content: '?';
}

.card-back {
  transform: rotateY(180deg);
  font-size: 3rem;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
}

/* Card colors */
.card[data-color="0"] .card-back { background: #fff3e0; color: #e65100; }
.card[data-color="1"] .card-back { background: #e8f5e9; color: #2e7d32; }
.card[data-color="2"] .card-back { background: #fce4ec; color: #c62828; }
.card[data-color="3"] .card-back { background: #e3f2fd; color: #1565c0; }
.card[data-color="4"] .card-back { background: #f3e5f5; color: #6a1b9a; }
.card[data-color="5"] .card-back { background: #fff8e1; color: #f57f17; }

/* Matched */
.card.matched .card-back {
  box-shadow: 0 0 16px rgba(76, 175, 80, 0.6);
}

.card.matched .card-inner {
  animation: matchBounce 0.4s ease;
}

@keyframes matchBounce {
  0%   { transform: rotateY(180deg) scale(1); }
  50%  { transform: rotateY(180deg) scale(1.12); }
  100% { transform: rotateY(180deg) scale(1); }
}

/* Disabled while checking */
.card.disabled {
  pointer-events: none;
}

/* Overlay */
.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.45);
  display: none;
  justify-content: center;
  align-items: center;
  z-index: 100;
}

.overlay.visible {
  display: flex;
}

.overlay-content {
  background: #fff;
  border-radius: 20px;
  padding: 40px 32px;
  text-align: center;
  max-width: 340px;
  width: 90%;
  box-shadow: 0 12px 40px rgba(0, 0, 0, 0.25);
}

.star {
  font-size: 4rem;
  margin-bottom: 8px;
}

.overlay-content h2 {
  font-size: 2rem;
  color: #2e7d32;
  margin-bottom: 8px;
}

.overlay-content p {
  font-size: 1.1rem;
  color: #555;
  margin-bottom: 20px;
}

.play-again-btn {
  background: linear-gradient(145deg, #66bb6a, #43a047);
  color: #fff;
  border: none;
  border-radius: 12px;
  padding: 14px 36px;
  font-size: 1.2rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
  box-shadow: 0 4px 12px rgba(67, 160, 71, 0.4);
}

.play-again-btn:hover {
  transform: scale(1.05);
}

.play-again-btn:active {
  transform: scale(0.97);
}

/* Responsive */
@media (max-width: 400px) {
  .grid {
    gap: 8px;
  }

  .card-back {
    font-size: 2.4rem;
  }

  .card-front {
    font-size: 1.6rem;
  }

  h1 {
    font-size: 1.8rem;
  }
}