Slightly exaggerated numbers there, but how bad can a css selector really be to the client experience when it's likely based on today's UI dev trends that we're loading 3mb of react + other JS
I wish I was exaggerating, that's something I recently had to deal with :(
You're right, "I need an OS written in JS to run before I can toggle that menu" dwarfs all of it. I'm lucky in that regard, I usually deal with jQuery-based things; you can still trim 95% of the code if you got rid of it (carousels are stopping me, people love carousels), but even if you don't, you land at like 100kb JS and you can defer it.
