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

body {
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  background-color: #333;

  flex-direction: column;
  gap: 20px;
}

#myCanvas {
  background-color: black;
  box-shadow: 0 0 10px rgba(0, 0, 0, 0.5);
}

#startButton {
  margin-bottom: 20px;
  padding: 12px 25px;
  font-size: 1.2rem;
  font-weight: bold;
  color: white;
  background-color: #4caf50; /* 綠色 */
  border: none;
  border-radius: 5px;
  cursor: pointer;
  box-shadow: 0 4px #999;
  transition: all 0.1s ease-in-out;
}

#startButton:hover {
  background-color: #45a049;
}

#startButton:active {
  background-color: #45a049;
  box-shadow: 0 2px #666;
  transform: translateY(2px);
}