You don't need to use different languages to decouple things. A common pattern in React is to decouple logic and style using presentational components and conta

You don't need to use different languages to decouple things. A common pattern in React is to decouple logic and style using presentational components and container components (there are lots of articles on it if you Google those two terms), and I find that split to be much more natural than trying to split up HTML, JS, and CSS (which often need to cooperate with each other). One good practice with CSS-in-JS is to only use CSS in presentational components.