body {
  margin: 0;
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  background-color: #f4f4f4;
}

.game-container {
  position: relative;
  text-align: center;
}

canvas {
  border: 2px solid black;
  background-color: white;
  display: block;
}

#restartBtn {
  margin-top: 10px;
  padding: 10px 20px;
  font-size: 16px;
  background-color: #007bff;
  color: white;
  border: none;
  cursor: pointer;
  display: none;
}

#restartBtn:hover {
  background-color: #0056b3;
}