* fix: Firefox fallback breaks right-edge fade in related content (#133X)
Firefox does not support scroll-driven animations by default, causing
the animation to fall back to a 0s time-based animation that jumps to
the last keyframe — flipping the fade from right to left.
Wrap animation properties in @supports (animation-timeline: scroll())
so Firefox degrades gracefully to a static right-edge fade.
* chore: fix identation
* fix: add back wrongly deleted props
