Ok maybe I was too negative too quickly, sorry. After reading another article [1] linked in some other comment I can see the appeal, if used with some templating engine that allows reusing html (like Vue or React).

It is crazy how new technology brings up old patterns again. Similar to how it was frowned upon to have JS near your HTML ("must be separated!") and now with React they are intertwined to a maximum.

I oftentimes find css to be the most complex and hardest to change part of web applications and am thankful to any approach that explores alternatives!

[1] https://adamwathan.me/css-utility-classes-and-separation-of-...