react.dev/content/docs/faq-styling.md

id, title, permalink, layout, category

id	title	permalink	layout	category
faq-styling	Styling and CSS	docs/faq-styling.html	docs	FAQ

How do I add CSS classes to components?

Pass a string as the className prop:

render() {
  return <span className="menu navigation-menu">Menu</span>
}

Can I use inline styles?

Yes, see https://reactjs.org/docs/dom-elements.html#style

Are inline styles bad?

CSS classes are generally more efficient than inline styles.

What is CSS-in-JS?

CSS-in-JS refers to a pattern where CSS is written with Javascript, then extracted into a stylesheet.

Comparison of CSS-in-JS Libraries

Can I do animations in React?

React can be used to power animations. See React Transition Group, for example.