/**
 * Back to top button.
 */
.back-to-top {
  position: fixed;
  bottom: 15vh;
  z-index: 100;
  right: var(--s-lg);
  text-align: right;
  visibility: hidden;
  opacity: 0;
  transition: opacity 300ms ease-in-out;
}
@media (min-width: 768px) {
  .back-to-top {
    right: var(--s-4xl);
  }
}
.back-to-top.is-visible {
  visibility: visible;
  opacity: 1;
}