Note: There is a bug that is fixed in the upcoming Hugo 0.76 where styles are not rebuilt when your Tailwind or PostCSS config changes. If you want that sooner you can build Hugo from source.
A very simple starter set up with TailwindCSS and its typograhpy plugin and a build setup using PostCSS and PurgeCSS (when running the production build).
This setup can be used both as a starter project and a theme.
npm install
hugo server
Import it into your project, and then run:
hugo mod npm pack
npm install
Then run your project as usual.