animation: fadein 0.5s ease-in forwards;
  opacity: 0;
  animation-delay: ${(props: ISliderItem) =>
    props.animationOffset ? `${props.animationOffset * 300}ms` : 0};
  @keyframes fadein {
    from {
      opacity: 0;
    }
    to {
      opacity: 1;
    }
  }

  use the index as the animation offset on the container that renders the children you want to animate in.