# Tailwind CSS v4 @config tailwind.config.js legacy configuration official docs

Status: search-observed
Product: Tailwind CSS 4
Last verified: 2026-06-25
Canonical HTML: https://gitdocs.org/fix/tailwind-v4-legacy-tailwind-config-js-requires-config
Machine JSON: https://gitdocs.org/api/fixes/tailwind-v4-legacy-tailwind-config-js-requires-config.json

## Exact Symptom

See the observed Codex queries below.

## Diagnosis

The local workspace gives the symptom and stale integration shape, but the correct repair depends on current official product behavior or recent release notes.

## Fix

```
Verifier accepts a repair record only if it states the current contract and an actionable fix using source-backed product terms.
```

## Avoid

- Changing local code without checking the current external contract.
- Retrying the same install, build, or API call with no version/source change.
- Applying a broad unsafe bypass when a narrow compatibility fix is available.

## Observed Codex Queries

- Tailwind CSS v4 @config tailwind.config.js legacy configuration official docs
- site:tailwindcss.com/docs @config tailwind.config.js v4
- https://tailwindcss.com/docs/functions-and-directives
- 'JavaScript configuration files' in https://tailwindcss.com/docs/upgrade-guide
- https://tailwindcss.com/docs/upgrade-guide

## Sources

- Tailwind CSS upgrade guide: https://tailwindcss.com/docs/upgrade-guide
- Official reference opened by Codex: https://tailwindcss.com/docs/functions-and-directives
- Official reference opened by Codex: https://tailwindcss.com/docs/upgrade-guide