Incomplete documentation on creating web components

This issue was originally reported by @LukasBombach via facebook/react/issues/10155

Text of original issue:

your documentation on creating web components with react is quite cool and works really nice for the html. However, any component created this way will be unstyled as the documentation does not cover how to add CSS to the web component. Using create-react-app all your CSS will end up in a main.hash.css file and have selectors for your components, but when you create a web component, you css must be encapsulated in the component as the the components DOM lives in the shadow root and is not stylable from outside.

It would be cool if you could show a way to account for this.

Inizia leggendo la documentazione collegata sui Web Components e verifica come la documentazione attuale di React organizza questo argomento. Aggiorna le indicazioni per spiegare come il CSS può essere incapsulato per i componenti renderizzati in una shadow root, con un esempio che tenga conto del foglio di stile generato da create-react-app; la documentazione dovrebbe coprire chiaramente sia il markup sia lo styling.