Astro.build homepage surprisingly slow to scroll in Firefox once fully loaded

[dandv]

I was evaluating site generators and looked at Astro. Tested against https://astro.build in Firefox 121.0 64-bit on Fedora 38. Issue does not occur in Chromium or on other sites in Firefox.

Describe the Bug

After astro.build is completely loaded, scrolling is surprisingly slow, with portions of the webpage needing up to one second to re-render (see screencast). Firefox isn't able to keep up with rendering if holding PgUp/PgDn for auto-repeat.

This may well be a Firefox issue. However, it can turn off those who evaluate Astro for their needs using Firefox, so it's in Astro's interest to report the issue upstream and find a workaround in the interim.

Screencast

https://youtu.be/jQHYtrnQg5U

[bluwy]

Possible duplicate of #736