LightningCSS breaking change with Vite 8?

[hansmbakker]

Vite 8 support was added in #19790.

@rozsazoltan mentioned in #19789 (comment) that there is a breaking change in Vite 8 regarding the use of LightningCSS which might need some additional fixes to let TailwindCSS and Vite share the LightningCSS configuration.

[RobinMalfait]

The Lightning CSS inside of Vite will run on top of the output we produce. Are you experiencing any issues right now?

For example, @rozsazoltan mentioned a requirement for these settings:

import { defineConfig } from "vite";
import tailwindcss from "@tailwindcss/vite";

export default defineConfig({
  css: {
    transformer: 'postcss', // default: 'lightningcss'
  },
  build: {
    cssMinify: 'esbuild', // default: 'lightningcss'
  },
  plugins: [
    tailwindcss(),
  ],
});

But in my testing that's not necessary, so I might be missing something here.

One thing you can do with the Lightning CSS config is to change the targets you want to compile for. If you want to compile for different browsers, then that should just work.

So I would love to learn more about the actual issues people are running into before we expose Lightning CSS configuration options if it turns out that you don't actually need them. Additionally, esbuild in Vite <8 and nano-css in some versions of Next.js already had different logic related to minification for example.

[hansmbakker]

I hadn't had the time yet to try it myself, but I saw the warnings about this in several places (when googling for "tailwindcss vite 8") and decide to reach out to ensure it wouldn't be an issue when upgrading.

Thank you for looking into this and apologies if it was a false alarm.

[JammingBen]

When building my Vue component library that uses Tailwind, I get a lot of errors using LightningCSS: [lightningcss minify] Unknown at rule: @apply. So it seems that it doesn't know the @apply directive, which I guess is expected when using Vite's LightningCSS config...?

I didn't have the time to dig into it though. Setting cssMinify to esbuild works as expected, which is fine for the time being. But it would be nice to use LightningCSS eventually.

[wongjn]

@JammingBen I think the @apply statements shouldn't exist by the time Vite's Lightning CSS sees the CSS. Consider providing a reproduction.

[JammingBen]

Ahh you're right, I had another issue on my side. Works just fine now. Sorry for the noise!

[sydneyvaughn75-ops]

Let me know if I need more help here

…

On Mon, Mar 16, 2026, 11:11 AM Jannik Stehle ***@***.***> wrote: *JammingBen* left a comment (tailwindlabs/tailwindcss#19792) <#19792 (comment)> Ahh you're right, I had another issue on my side. Works just fine now. Sorry for the noise! — Reply to this email directly, view it on GitHub <#19792 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HZNKZCWKT76JXPQT6N73L4RARTZAVCNFSM6AAAAACWQWOPSSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DANRYHA2TIMRTHA> . You are receiving this because you are subscribed to this thread.Message ID: ***@***.***>

[RobinMalfait]

We've bumped Lightning CSS and Vite to the latest version so all the versions line up now. If you are running into issues and end up on this particular issue, feel free to open a new issue with a minimal reproduction repo attached so we can take a look at what's going on.

In my testing, it seems like the code we generate, and the Lightning CSS that runs after our code as part of other devtools (Vite) seem to work correctly together.

Thanks!

[sydneyvaughn75-ops]

Appreciate the update

…

On Thu, Mar 19, 2026, 6:17 AM Robin Malfait ***@***.***> wrote: *RobinMalfait* left a comment (tailwindlabs/tailwindcss#19792) <#19792 (comment)> We've bumped Lightning CSS and Vite to the latest version so all the versions line up now. If you are running into issues and end up on this particular issue, feel free to open a *new* issue with a minimal reproduction repo attached so we can take a look at what's going on. In my testing, it seems like the code we generate, and the Lightning CSS that runs *after* our code as part of other devtools (Vite) seem to work correctly together. Thanks! — Reply to this email directly, view it on GitHub <#19792 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/B7HZNKZ7PCWTTWOOP4KQJA34RPJMDAVCNFSM6AAAAACWQWOPSSVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHM2DAOBZGQYTOOBSGA> . You are receiving this because you commented.Message ID: ***@***.***>