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

body {
  font-family: sans-serif;
  background: #f0f0f0;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 1rem;
}

h1 {
  margin-bottom: 1rem;
}

.game-board {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
  gap: 10px;
  max-width: 600px;
  width: 100%;
}

.card {
  background: #444;
  height: 100px;
  border-radius: 10px;
  cursor: pointer;
  color: white;
  font-size: 2rem;
  display: flex;
  justify-content: center;
  align-items: center;
  user-select: none;
}

.card.revealed {
  background: #00bcd4;
}

#modeSelect {
  display: flex;
  gap: 1rem;
  margin-bottom: 1rem;
}

.mode-button {
  padding: 1rem 2rem;
  font-size: 1.5rem;
  border: none;
  border-radius: 10px;
  background-color: #4caf50;
  color: white;
  cursor: pointer;
  transition: background-color 0.3s;
}

.mode-button:hover {
  background-color: #388e3c;
}

#gameControls {
  margin-top: 1rem;
  display: flex;
  gap: 1rem;
}

#gameControls button {
  padding: 0.8rem 1.5rem;
  font-size: 1.2rem;
  border: none;
  border-radius: 10px;
  background-color: #2196f3;
  color: white;
  cursor: pointer;
  transition: background-color 0.3s;
  margin-bottom: 10px;
}

#gameControls button:hover {
  background-color: #1976d2;
}