body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #f0f0f0;
}

.board {
  display: grid;
  grid-template-columns: repeat(4, 100px);
  gap: 10px;
  justify-content: center;
  margin-top: 20px;
}

.card {
  width: 100px;
  height: 100px;
  background: #2e3a59;
  color: white;
  display: flex;
  justify-content: center;
  align-items: center;
  font-size: 2em;
  cursor: pointer;
  border-radius: 8px;
  user-select: none;
  transition: transform 0.3s, background 0.3s;
}

.card.flipped {
  background: #f9ca24;
  color: black;
  transform: rotateY(180deg);
}

.card.matched {
  background: #6ab04c;
  color: white;
  cursor: default;
}