rails has nothing to do with the rendered page size though. Congrats on the perfect lighthouse score.
All the Tailwind building and so on is done using common JS tools, which are mostly standard out of the box Rails 8 supplied scripts!
Sprockets used to do the SASS compilation and asset bundling, but the Rails standard now is to facilitate your own preferences around compilation of CSS/JS.
It was more a quick promote Rails comment as it can get dismissed as not something to build fast website in :-)