body {
  margin: 0;
  overflow: hidden;
  background: black;
}

canvas {
  display: block;
}
/* VR 切换按钮样式 */
#vrToggleBtn {
  position: fixed;
  top: 20px;
  right: 20px;
  z-index: 9999;
  padding: 12px 20px;
  font-size: 16px;
  background: #0078ff;
  color: white;
  border: none;
  border-radius: 8px;
  cursor: pointer;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
}
#vrToggleBtn:hover {
  background: #005fcc;
}