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.

Commencez par lire la documentation liée sur les Web Components et examinez la manière dont la documentation actuelle de React organise ce sujet. Mettez à jour les instructions pour expliquer comment le CSS peut être encapsulé pour les composants rendus dans une shadow root, avec un exemple qui tient compte de la feuille de style générée par create-react-app ; la documentation doit couvrir clairement à la fois le balisage et le style.