body { background-attachment: fixed; background-position: center; }
.space-background {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
}
#app { position: relative; z-index: 1; }
.space-background[hidden] { display: none; }
@media (prefers-reduced-motion: reduce) {
  .space-background { display: none; }
}