body {
  font-family: Arial, sans-serif;
  text-align: center;
  background: #f4f4f4;
  margin: 0;
  padding: 20px;
}

#puzzle-container {
  width: 480px;
  height: 480px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2px;
}

.piece {
  width: 160px;
  height: 160px;
  background-size: 480px 480px;
  cursor: pointer;
  border: 1px solid #ccc;
}