.game-board {
  display: grid;
  grid-template-columns: repeat(4, 1fr); /* Cuatro cartas por fila */
  gap: 10px;
  margin-bottom: 20px;
}

.card {
  width: 100px;
  height: 100px;
  display: flex;
  align-items: center;
  justify-content: center;
  background:url(reverso.png);
  color: white;
  font-size: 24px;
  font-weight: bold;
  border-radius: 4px;
  cursor: pointer;
  user-select: none;
  transition: background-color 0.3s ease;
  position: relative;
}

.card.flipped {
  background: #ffffff;
  color: #333;
}

.card:active {
  background-color: #0056b3;
}

.button {
  padding: 10px 20px;
  background-color: #28a745;
  color: white;
  border: none;
  border-radius: 4px;
  cursor: pointer;
  font-size: 16px;
  transition: background-color 0.3s ease;
}

.button:hover {
  background-color: #218838;
}