- Which Tailwind version?
- v3.4+. The core utility classes have been stable since v2; v3 added arbitrary values `[]` and JIT; v3.4 added container queries.
- Does it cover arbitrary values?
- Yes — `w-[calc(100%-2rem)]`, `bg-[#1a1a2e]`. Essential for one-off designs that don't fit the default scale.
- What about responsive variants?
- All five: sm, md, lg, xl, 2xl. Plus the mobile-first philosophy (default = mobile, variants scale up).
- Dark mode?
- Yes — both the `class` strategy (recommended) and the `media` strategy. Plus how to toggle in JS.