Hi Victoria,
I tend to disagree on the part you hardly use Vanilla CSS.
I'm my company we almost solely use Vanilla CSS Because of the non basic designs we get.
We do however write our own SASS "tailwind" basics with all margin/colors and paddings.
Tailwind itself I think would be a good fit, but I would strongly advise people to try and recreate massive sites like Facebook in pure CSS. Just for the experience :D
(Or make CSS Art)