.stack-slider {
  position: relative;
  width: 100%;
  aspect-ratio: 16 / 9;
}

.stack-slider img {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;

  border-radius: 12px;

  opacity: 0;
  animation: stackFade 15s infinite;
}

/* Zeitversatz */
.stack-slider img:nth-child(1) { animation-delay: 0s; }
.stack-slider img:nth-child(2) { animation-delay: 3s; }
.stack-slider img:nth-child(3) { animation-delay: 6s; }
.stack-slider img:nth-child(4) { animation-delay: 9s; }
.stack-slider img:nth-child(5) { animation-delay: 12s; }

@keyframes stackFade {
  0%   { opacity: 0; }
  5%   { opacity: 1; }
  20%  { opacity: 1; }
  25%  { opacity: 0; }
  100% { opacity: 0; }
}