#snow{
  position: fixed;
  left: 0; top: 0;
  width: 100vw;
  height: 100vh;
  z-index: 9999;
  pointer-events: none !important; /* важно */
  user-select: none;
}
@media (prefers-reduced-motion: reduce){
  #snow{ display: none !important; }
}