I write my own css for my statically generated website (andrewzah.com). The problem with bootstrap etc is exactly that they’re aimed at being generic. They’re not specific enough to do what I want quite how I want it… and there’s the burden of learning them.

It’s a lot easier to start with a good, semantic html structure and come up with exactly the CSS that one needs, rather than continually fight a system aimed at no one in particular.

Not to mention the bloat of unnecessary CSS/JS that you don’t actually need.