body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #f0f0f0;
  margin: 0;
  padding: 20px;
}

h1 {
  color: #333;
}

#startBtn {
  padding: 10px 20px;
  font-size: 18px;
  margin: 15px 0;
  cursor: pointer;
}

.board {
  display: grid;
  grid-template-columns: repeat(3, 100px);
  grid-template-rows: repeat(3, 100px);
  gap: 5px;
  justify-content: center;
  margin: 20px auto;
}

.cell {
  width: 100px;
  height: 100px;
  background: white;
  border: 2px solid #444;
  display: flex;
  justify-content: center;
  align-items: center;
  cursor: pointer;
}

.cell img {
  width: 80%;
  height: 80%;
  object-fit: contain;
}