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We use .less files (due to the fact we use antd and we have to use Less to modify it), and just use webpack import's to import them. After we build our app, we have .html files that includes all stylesheets. This file is then used as a template on the server.

If you want to use styled-components on the server you have to wrap your entire application in ServerStyleSheet collector that would collect all of your styles from components. After it's done you can just retrieve normal style tags from it and add it to your page. Take a look here: https://www.styled-components.com/docs/advanced#server-side-rendering

I had been using sass for a while. Transition to styled-component took me sometime to get used to it haha.

I like the way styled-jsx works. It feels like normal CSS but has some great features (scoped to current component, works on SSR).

If you are working on new app and want to have SSR I recommend checking out Next.js.

Currently I am still using Express or Koa for SSR haha.

I am also looking on this jss where Material-UI is using this.