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Fix : Error with lightningcss when using Tailwind CSS v4 with Next.js 15.2.1 and Node.js 20.18.3

Fresh3 days ago
Mar 14, 20260 views
Confidence Score55%
55%

Problem

Getting Error with lightningcss when using Tailwind CSS v4 with Next.js 15.2.1 and Node.js 20.18.3 using create-next-app@latest . --use-pnpm version of Tailwind CSS v4.0.12 (via @tailwindcss/postcss) build tool framework Next.js 15.2.1 with Turbopack version of Node.js v20.18.3 browser N/A (Build error) operating system Windows 10 Repo URL https://github.com/abhishekkumar35/blogcodeabode also attached terminal messages in a saparate md file name terminalmessage.md(can be found in repo) 1. Create a new Next.js project with Tailwind CSS: [code block] (Select Yes for Tailwind CSS, TypeScript, ESLint, App Router, and Turbopack) 2. Run the development server: [code block] Describe your issue When running a Next.js 15.2.1 application with Tailwind CSS v4, I'm getting the following error related to lightningcss: [code block] The application fails to compile CSS and returns a 500 error. This appears to be an issue with the lightningcss dependency that Tailwind CSS v4 uses. My package.json dependencies: [code block] the application is expected to compile and run without errors.

Error Output

Error with lightningcss when using Tailwind CSS v4 with Next.js 15.2.1 and Node.js 20.18.3 using create-next-app@latest . --use-pnpm**

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1 Fix

Canonical Fix
Unverified Fix
New Fix โ€“ Awaiting Verification

Fix lightningcss Error in Tailwind CSS v4 with Next.js 15.2.1

Medium Risk

The error with lightningcss when using Tailwind CSS v4 in a Next.js 15.2.1 application is likely due to incompatibilities between the versions of Tailwind CSS and the lightningcss dependency. This can occur when the CSS compilation process fails due to missing configurations or incompatible versions of dependencies.

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  1. 1

    Update Tailwind CSS

    Upgrade Tailwind CSS to the latest version to ensure compatibility with Next.js and lightningcss.

    bash
    pnpm add tailwindcss@latest
  2. 2

    Check lightningcss Version

    Ensure that the lightningcss version is compatible with the updated Tailwind CSS. You may need to update or install the latest version of lightningcss.

    bash
    pnpm add lightningcss@latest
  3. 3

    Update PostCSS Configuration

    Verify and update your PostCSS configuration file (postcss.config.js) to ensure it includes the necessary plugins for Tailwind CSS and lightningcss.

    javascript
    module.exports = { plugins: [require('tailwindcss'), require('autoprefixer'), require('lightningcss')] };
  4. 4

    Clear Cache and Rebuild

    Clear any cache and rebuild the Next.js application to ensure all dependencies are correctly loaded.

    bash
    pnpm run build && pnpm run dev
  5. 5

    Check for Additional Errors

    After rebuilding, monitor the terminal for any additional errors related to CSS compilation or dependencies.

    bash
    tail -f terminalmessage.md

Validation

Confirm that the application compiles successfully without errors and that the development server runs without issues. Check the terminal output for any remaining errors related to CSS.

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Environment

Submitted by

AC

Alex Chen

2450 rep

Tags

tailwindcsscssneeds-reproduction