Frontend & browser·Layout, CSS and the cascade
the styles are written next to the component and injected into a style tag when it first renders.
CSS-in-JS
Also calledstyled components, runtime styling
Declaring styles in JavaScript so they can be colocated with a component and computed from its props. It gives real scoping and dynamic values without a build convention, at the cost of shipping the styling engine to the browser and doing style work during render. Runtime libraries interact badly with server rendering and streaming, which is why the ecosystem has been moving back toward compile-time extraction.