That error appears to be caused because the peer dependency postcss has not been installed. In npm some packages include dependencies and others expect that dependency too already exist on the environment. Using peer dependencies instead of packaging dependencies results in less conflicts, smaller packages, and less repetition.
I think there might be a typo in the docs instead postcss should be the first package that is installed.
I’ve never heard of this package until today so this is just based on my initial look at the docs.
Tailwind css does look pretty cool. I think I might be adding that to my own personal project to orchestrate micro-frontends and cms content. That would be perfect to allow people add css without needing perhaps a more complex approach.