Am I having a hard time understanding this CSS in JS concept, and therefore Styletron, if I've never worked with React before? Let's say at a basic level, I hav

Am I having a hard time understanding this CSS in JS concept, and therefore Styletron, if I've never worked with React before? Let's say at a basic level, I have compiled stylesheets -- could you explain in simple web developer layman's terms how this could be implemented, knowing the benefit of reduced file size and increased performance is what were aiming for?