where do i put rails 6 stylesheets

?

app/assets/stylesheets/

Try that spot? – H

Rails 6 supports both sprockets (the assets pipeline) and webpacker by default, you can use any of those. You can use app/assets/stylesheets as of previous rails versions that didn’t have webpacker or you can follow webacker’s readme on CSS https://github.com/rails/webpacker/blob/master/docs/css.md