Bootstrap and numerous other popular CSS frameworks, notably any with grid layout and/or utility classes, have done that for the past decade+. So Tailwind is the modern/popular CSS framework?
Other frameworks generally combine multiple properties with their classes.
It is a very different design choice with it's own up and downsides but equating it to bootstrap is just silly.
It's more realistic to compare it to directly setting style attributes on html tags then bootstrap, but that wouldn't let you use responsive modifiers/dark mode nor be as concise.
Reinventing the wheel by subdividing all of your css into individual classes and combining them in html again just doesn't seem like a step forward to me.
Including responsive classes? i.e. make this div X rem on mobile, Y rem on tablets, and Z rem on desktop? With 3 class attributes that require no config?