Animation performance

Variable font animations should be made as performant as possible:

- Use requestanimationframe when triggering from JS
- Use Intersection Observer to detect elements in view
- Debounce/throttle?

No files or tests are identified. Start by locating the JavaScript that triggers variable font animations, then evaluate requestAnimationFrame and Intersection Observer usage along with debouncing or throttling. Done means animations remain correct while performance improves, but the issue does not define a benchmark or acceptance threshold.

Written by the indexing model from the issue text.