Short answer: stop your server, run rails assets:clobber, and restart your server.
I guess the question I have to ask: why did you run bin/rails assets:precompile? What that does is to create a static snapshot of your tailwind classes and put the results into your public/assets directory. If that directory exists when the server is started, puma will serve those files and never forward the request to rails at all. The end result is any tailwind classes you try to make use of will be ignored unless they are in that static snapshot.