Tailwind CSS documentation lookup

This project (HostedGPT) styles its Hotwire-rendered views with Tailwind CSS via the tailwindcss-rails gem. Tailwind v3 and v4 differ substantially — v3 uses a JS config file (tailwind.config.js, module.exports = { theme: {...} }), v4 uses CSS-first config (@import "tailwindcss" + @theme blocks in the stylesheet, often no JS config file at all) and renamed/changed a number of utilities. Trained knowledge can silently mix the two, so confirm which version this project is on before trusting either.

Determine the version first

Check the repo structure rather than assuming:

ls config/tailwind.config.js 2>/dev/null   # present + module.exports = v3-style config
grep -rn '@theme' app/assets/stylesheets/ 2>/dev/null   # present = v4-style CSS config
grep -m1 'tailwindcss-rails (' Gemfile.lock

A present config/tailwind.config.js using module.exports (no @theme blocks in the CSS) means this project is on Tailwind v3. If that ever flips — tailwind.config.js disappears and @theme shows up in the stylesheet instead — the project has moved to v4, and this skill's default assumption below no longer holds.

Sources

• Docs: https://tailwindcss.com/docs
  • The current site defaults to the latest major version's docs, which won't match a v3 project.
  • If you determined this project is still on v3, prefer the v3-pinned docs at https://v3.tailwindcss.com/docs/... instead of the default (v4-or-later) docs site.
  • If a page's syntax looks like v4 (CSS @import "tailwindcss" / @theme blocks, no tailwind.config.js in examples) but the project is on v3, that's a mismatch — look for the v3-equivalent page instead.

When to look things up

Use WebFetch when:

• You need the exact utility class name/values for something (spacing scale, color palette, arbitrary value syntax) rather than guessing.
• You're customizing the theme/config and need the config shape for the version this project actually uses (JS config for v3, CSS @theme for v4).
• You're unsure whether a utility/variant exists in the installed major version (some utilities and variants only exist in v4, or were renamed from their v3 equivalents).

Skip the lookup for basic, version-stable utilities you're confident about (e.g. flex, items-center, p-4), or when the existing codebase already shows the exact class/pattern to follow — check app/views/ and the project's Tailwind config for this project's own conventions first.