I meant the CSS modules that are implemented by a build tool. And yes, mea culpa, they are probably a js-only solution, requiring a build tool to correctly interpret a css import (.module.css in the file name is a common convention; but it is tweakable), and the author to use the imported object instead of plain strings, when referring to the class names. But I don't know if having to write `class="styles.foo"` as opposed to `class="foo"` counts as learning. And apart from that, there isn't anything else to learn.

But, given that one would need build tools for tailwind as well, the requirement for build tools couldn't have played a role in the choice between the two.