:root {
  --fade-distance: 24px;
  --fade-duration: 1s;
  --fade-easing: cubic-bezier(0.22, 1, 0.36, 1);
  --fade-stagger: 0.05s;
}

/* hidden state — scoped to .js so a broken script can never blank the page */
.js .fade-up {
  opacity: 0;
  transform: translateY(var(--fade-distance));
}

/* the transition itself — always defined */
.fade-up {
  transition:
    opacity   var(--fade-duration) var(--fade-easing),
    transform var(--fade-duration) var(--fade-easing);
  transition-delay: var(--fade-delay, 0s);
  will-change: opacity, transform;
}

/* revealed state — the script adds .is-visible */
.js .fade-up.is-visible {
  opacity: 1;
  transform: translateY(0);
  will-change: auto;
}

/* stagger: helper classes */
.fade-up--d1 { --fade-delay: calc(var(--fade-stagger) * 1); }
.fade-up--d2 { --fade-delay: calc(var(--fade-stagger) * 2); }
.fade-up--d3 { --fade-delay: calc(var(--fade-stagger) * 3); }
.fade-up--d4 { --fade-delay: calc(var(--fade-stagger) * 4); }
.fade-up--d5 { --fade-delay: calc(var(--fade-stagger) * 5); }
.fade-up--d6 { --fade-delay: calc(var(--fade-stagger) * 6); }

/* stagger: automatic, for a grid wrapper */
.fade-up-group > .fade-up:nth-child(1) { --fade-delay: calc(var(--fade-stagger) * 0); }
.fade-up-group > .fade-up:nth-child(2) { --fade-delay: calc(var(--fade-stagger) * 1); }
.fade-up-group > .fade-up:nth-child(3) { --fade-delay: calc(var(--fade-stagger) * 2); }
.fade-up-group > .fade-up:nth-child(4) { --fade-delay: calc(var(--fade-stagger) * 3); }
.fade-up-group > .fade-up:nth-child(5) { --fade-delay: calc(var(--fade-stagger) * 4); }
.fade-up-group > .fade-up:nth-child(6) { --fade-delay: calc(var(--fade-stagger) * 5); }

/* size variants */
.fade-up--sm { --fade-distance: 12px; --fade-duration: 0.45s; }
.fade-up--lg { --fade-distance: 48px; --fade-duration: 0.8s;  }


.fade-up--still { --fade-distance: 0px; }
/* accessibility */
@media (prefers-reduced-motion: reduce) {
  .js .fade-up,
  .js .fade-up.is-visible {
    opacity: 1;
    transform: none;
    transition: none;
    transition-delay: 0s;
    will-change: auto;
  }
}