.js-scroll-left {
  opacity: 0;
  transform: translate3d(-40px, 0, 0);
  transition: .5s;
}

.js-scroll-right {
  opacity: 0;
  transform: translate3d(+40px, 0, 0);
  transition: .5s;
}

.scroll-left,
.scroll-right {
  opacity: 1;
  transform: translate3d(0, 0, 0);
}