/* Starfield */
.stars {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  pointer-events: none;
  z-index: 0;
}

.star {
  position: absolute;
  width: 2px;
  height: 2px;
  background: #fff;
  border-radius: 50%;
  animation: twinkle var(--duration) ease-in-out infinite;
  opacity: 0;
}

@keyframes twinkle {
  0%, 100% { opacity: 0; }
  50% { opacity: var(--brightness); }
}