I've been struggling to work with this project I inherited that uses Tailwind CSS. I kept trying to use Tailwind styles that were clearly listed in the documentation, but most of them didn't work. When I checked the bundled CSS generated by Webpack, the styles that didn't work weren't present. Which seemed weird! Seeing as how they were official styles listed in the documentation.
It turns out that Tailwind "helps" you at the build stage by monitoring your source files, and only including styles in your output bundle that you actually used somewhere. So if you ever want to use a new Tailwind style, you have to put it in somewhere and then npm rebuild the whole bundle
The very first thing that attracted me to web development back in the early '90s was "hey, I can build useful stuff this way without having to deal with a compile step!"