[cynicalsecurity]

Doesn't work correctly in Firefox.

Feels sluggish, but maybe this could be fixed by reducing the transition time.

But why? People usually don't notice such transition effects and it doesn't affect user experience in any meaningful positive way. It feels absolutely unnecessary.

Maybe you could re-use it as a mod for some game engine. This feels appropriate for video games; not for web-sites.

[solarkraft]

I have the exactly opposite view, possibly with the same amount of conviction. It feels very necessary to communicate hierarchy and where things are coming from and going. It communicates a lot of important information and continuity. In real life, you don’t have things suddenly appearing and disappearing all the time. That’s not how our brains are conditioned.

[tinchox6]

Firefox issues are real and I want to fix them. On the "why", fair to be skeptical, it's not for every UI. But I do think it makes sense when hierarchy needs to feel spatial.

[jvdvegt]

Weird, seems to work fine in Firefox on Android.