Astro, Vite, and Tailwind 4.0.8 throws this error: EISDIR: illegal operation on a directory, read

[mookman288]

What version of Tailwind CSS are you using?
4.0.8

What build tool (or framework if it abstracts the build tool) are you using?
astro 5.3.1 and @tailwindcss/vite 4.0.8

What version of Node.js are you using?
18.20.7

What browser are you using?
Chrome

What operating system are you using?
Windows

Describe your issue:

I'm following the guide here to install Astro and Tailwind:

https://tailwindcss.com/docs/installation/framework-guides/astro

When I run npm run dev or npm run dev --verbose or npm run astro --verbose dev I get the following error:

20:11:23 [ERROR] EISDIR: illegal operation on a directory, read
  Stack trace:
    at C:/...OMITTED.../src/styles/global.css
    [...] See full stack trace in the browser, or rerun with --verbose.

Even with the --verbose flag, I can't get anything else out of this error.

In a cursory search, I found no issues related to this particular error with this version of Tailwind, but I did see errors related to Vite not working well on Windows, and also not providing verbose error messages, but both of these issues are years old and already fixed.

I did see someone else in the Issues talk about how 4.0.8 has unrelated issues which downgrading resolves. I can confirm that downgrading to 4.0.7 seems to work and this error does not appear.

I hope this helps someone else who is having this exact problem.

[jarednapier]

Downgrading @tailwindcss/vite to 4.07 also worked for me.