:root { color-scheme: dark; background: #000; }
* { box-sizing: border-box; }
html, body, main { width: 100%; height: 100%; margin: 0; overflow: hidden; }
body { background: #000; }
main { position: fixed; inset: 0; height: 100dvh; }
.slide {
  position: absolute;
  inset: 0;
  display: block;
  width: 100%;
  height: 100%;
  object-fit: contain;
  opacity: 0;
  user-select: none;
  pointer-events: none;
  transition: opacity 1400ms ease-in-out;
}
.slide.visible { opacity: 1; }
@media (prefers-reduced-motion: reduce) { .slide { transition: none; } }