Vite build on Vue project produces false-positive warning regarding Vue :deep() selector

[mckennahampton]

What version of Tailwind CSS are you using?

v4.1.14

What build tool (or framework if it abstracts the build tool) are you using?

Vite 7.1.10, Vue 3.5.22, tailwindcss/vite 4.1.14

What version of Node.js are you using?

v22.18.0

What browser are you using?

N/A

What operating system are you using?

Linux (Ubuntu 24)

Reproduction URL

https://github.com/mckennahampton/tailwind-vite-isue

Describe your issue

@tailwindcss/vite v4.1.14 outputs console warnings during the vite build process when using @reference to bring in the CSS config file and also using a :deep() selector:

<style scoped>
@reference './style.css';

:deep(.logo) {
  background: black;
}
</style>

Found 1 warning while optimizing generated CSS: ... 'deep' is not recognized as a valid pseudo-class. Did you mean '::deep' (pseudo-element) or is this a typo?

Using tailwindcss/vite@4.1.13 does not produce any console output during build.

So far, I have not found a way to suppress the output in vite, so the only workaround I am aware of is to downgrade to 4.1.13

[wongjn]

It seems this could be due to #18918, such that the warning existed before, but is now shown in 4.1.14.

---

As an aside, <style> blocks are not generally recommended. You shouldn't need @reference in your snippet:

<style scoped>
:deep(.logo) {
  background: black;
}
</style>

And for the code in the provided repo, you could do:

:deep(.logo) {
  background-color: var(--color-red-500);
}

[mckennahampton]

There are some places in the project I am working on that still use the @apply rule and thus are bringing in the style config file via @reference. We are working on moving out any Tailwind CSS from style blocks, but that is a WIP

But yes that looks like the same issue in #18918, and I see this has already been triaged in #19094 and merged to main. So these warnings should at least be suppressed in one of the next releases Thanks for the insight @wongjn

[askomarov]

Is it fixed? I upgraded to 4.1.15 and the warning didn't go away. What else needs to be done?