#game-board {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 10px;
  max-width: 600px;
  margin: 20px auto;
  width: 100%;
}

.card {
  aspect-ratio: 1 / 1;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.5s;
  cursor: pointer;
  border-radius: 8px;
  box-shadow: 0 4px 8px rgba(0, 0, 0, 0.2);
}

.card-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  border-radius: 8px;
  display: flex;
  justify-content: center;
  align-items: center;
  user-select: none;
}

.card-back {
  background: linear-gradient(135deg, #f9d423 0%, #e65c00 100%);
  font-size: 24px;
  color: white;
}

.card-front {
  background-color: #ffffff;
  transform: rotateY(180deg);
  overflow: hidden;
}

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

.card.matched {
  transform: rotateY(180deg);
}

.card.matched .card-front {
  box-shadow: 0 0 10px 2px #4caf50;
}

.card-image {
  width: 90%;
  height: 90%;
  object-fit: contain;
}

#game-info {
  display: flex;
  justify-content: space-between;
  max-width: 600px;
  margin: 10px auto;
  font-size: 1.2em;
  font-weight: bold;
}

#difficulty-selector {
  margin: 15px auto;
  text-align: center;
}

.difficulty-button {
  padding: 8px 16px;
  margin: 0 5px;
  border: none;
  border-radius: 4px;
  background-color: #ddd;
  cursor: pointer;
}

.difficulty-button.selected {
  background-color: #f9d423;
  color: #333;
  font-weight: bold;
}

#game-controls {
  margin: 15px auto;
  text-align: center;
}

#new-game-button {
  padding: 10px 20px;
  border: none;
  border-radius: 4px;
  background-color: #4caf50;
  color: white;
  font-weight: bold;
  cursor: pointer;
  font-size: 1.1em;
}

/* Media queries for responsive design */
@media (max-width: 768px) {
  #game-board {
    max-width: 100%;
    gap: 8px;
  }
}

@media (max-width: 600px) {
  #game-board {
    grid-template-columns: repeat(4, 1fr);
    gap: 8px;
    max-width: 100%;
  }

  /* For extreme difficulty on smaller screens */
  #game-board[data-difficulty="extreme"] {
    grid-template-columns: repeat(6, 1fr);
    gap: 5px;
  }

  #game-info {
    padding: 0 10px;
    max-width: 100%;
  }

  .difficulty-button {
    margin: 3px;
    padding: 6px 12px;
    font-size: 0.9em;
  }
}

@media (max-width: 450px) {
  #game-board {
    grid-template-columns: repeat(3, 1fr);
    gap: 6px;
  }

  #game-board[data-difficulty="medium"] {
    grid-template-columns: repeat(4, 1fr);
    gap: 5px;
  }

  /* For extreme difficulty on very small screens */
  #game-board[data-difficulty="extreme"] {
    grid-template-columns: repeat(4, 1fr);
    gap: 4px;
  }
}

@media (max-width: 400px) {
  #game-board {
    grid-template-columns: repeat(3, 1fr);
    gap: 5px;
  }

  /* For extreme difficulty on very small screens */
  #game-board[data-difficulty="extreme"] {
    grid-template-columns: repeat(4, 1fr);
    gap: 3px;
  }

  #game-info {
    font-size: 1em;
    flex-direction: column;
    align-items: center;
    gap: 5px;
  }

  #difficulty-selector {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
  }

  .difficulty-button {
    margin: 3px;
    padding: 6px 10px;
    font-size: 0.9em;
  }

  #new-game-button {
    padding: 8px 15px;
    font-size: 1em;
  }
}

/* Dark mode styles */
.dark-mode #game-board .card-back {
  background: linear-gradient(135deg, #8a6b00 0%, #b34600 100%);
}

.dark-mode #game-board .card-front {
  background-color: #333;
}

.dark-mode .difficulty-button {
  background-color: #444;
  color: #ddd;
}

.dark-mode .difficulty-button.selected {
  background-color: #8a6b00;
  color: #fff;
}