chore: upgrade Tailwind from version 3 to 4

[MichaHuhn]

Upgrade Tailwind from version 3 to 4.

Tailwind 4 provides a simpler installation setup and offers some new features.

That's the installation guide for Tailwind version 4: https://tailwindcss.com/docs/installation/using-vite

[danieldietzler]

I am surprised the upgrade script messed up those deps? Have you done the upgrade manually?

[MichaHuhn]

I didn't use the upgrade script to avoid potential conflicts.
I uninstalled Tailwind instead and then installed Tailwind 4.

Based on the installation guide, those dependencies need to be installed as normal dependencies, right?

[danieldietzler]

That doesn't make sense to me. Vite is a dev dependency already, so @tailwindcss/vite wouldn't work anyways. Plus, in all projects I'm working on those are dev dependencies and it works perfectly fine.

It also makes sense: What the two do is simply generate CSS files and throw them into the build output. At runtime neither package is needed (which is good because having the entire tailwind lib in prod would be kind of annoying if you only use a couple of classes, hence tree shaking).

I have no idea why the docs would mess this up.

[MichaHuhn]

I agree. I just followed the docs.

[sebinside]

There seems to be an ongoing discussion about this: tailwindlabs/tailwindcss#13854

Nevertheless, I would also opt for keeping tailwind in the dev dependencies.

[MichaHuhn]

Weird that they didn't update the docs after this discussion.
They are now in the devDependencies.

The Dependabot updates created a merge conflict, so it's probably best if you resolve it @sebinside.