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

.game-board {
  width: 320px;
  margin: 20px auto;
  display: grid;
  grid-template-columns: repeat(4, 75px);
  gap: 10px;
}

.card {
  width: 75px;
  height: 75px;
  background: #444;
  color: white;
  font-size: 30px;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
  border-radius: 8px;
}

.card.flipped {
  background: #00aaff;
}