If you are looking to co-locate your CSS with React components then Fulcro does it: http://book.fulcrologic.com/#ColocatedCSS

@cjmurphy interesting... can I use with reagent?

On the server?

Not with Reagent, but you can use hiccup as long as it is in the render method of the component (which is just React render after all). If you are wanting a generic component (so no use of Fulcro's Om Next style state) then you could essentially just be using the CSS part of Fulcro. And users of the component would not know it is a Fulcro component as just passing in props. That's the theory anyway... And yes Fulcro does SSR, so your component could be on the server.