This is simply not the case. In order to use Tailwind, you need to know names of Tailwind classes, which are not part of the CSS standard. To say that Tailwind is just CSS is like saying that Ramda is just javascript.
> Your classes in your project are not part of the CSS standard either, by your definition
Yes, but my classes, by definition, are defined by me. The behavior of classes of a css framework is defined by someone else, who exposes an api for you to interact with these definitions. An api that you need to learn, in addition to just CSS.
It is no different from React, Lodash, Rxjs, etc. being "just javascript". They provide an additional DSL on top of the language itself.
This is simply not the case. In order to use Tailwind, you need to know names of Tailwind classes, which are not part of the CSS standard. To say that Tailwind is just CSS is like saying that Ramda is just javascript.