Hi, I am part of the Mozilla community. Mozilla devs read through comments and saw an issue with Firefox. They filed
https://bugzilla.mozilla.org/show_bug.cgi?id=1939643 to identify why it doesnt work only in Firefox.
Turns out other browsers do not follow the spec, and the underlying libraries that the page uses used workarounds to make it work in Chrome, but that broke Firefox.
We filed
https://github.com/tsparticles/tsparticles/issues/5443 (to fix the workaround in the library),
https://issues.chromium.org/issues/387030982 (Chrome bug to get it fixed there) and
https://bugzilla.mozilla.org/show_bug.cgi?id=1939701 (which creates a common webtest for all the browser vendors so that this functionality is tested in future and doesnt break).
All of this during the Holiday Season too!