@supports (animation-timeline: view(-50vh)) {
  .slide-timeline:not(:last-child) .slide-timeline-left,
  .slide-timeline:not(:last-child) .slide-timeline-right {
    opacity: 0.1;
    animation: scroll-reveal;
    animation-timeline: view(-50vh);
    animation-range: cover 0px;
  }
}

@keyframes scroll-reveal {
  0% {
    opacity: 0.1;
  }

  50% {
    opacity: 1;
  }

  100% {
    opacity: 0.1;
  }
}