DX: css prop similar to emotion, styled-components

__Describe the solution you'd like__
With [emotion](https://emotion.sh/docs/css-prop) and [styled-components](https://www.styled-components.com/docs/api#css-prop), you can provide a `css` prop that allows you to override a given component's styles.

Both libraries require a babel-plugin, and emotion requires a [`jsx` pragma.](https://emotion.sh/docs/css-prop#jsx-pragma)

__Are you willing to implement it?__
Willing? Yes. Able? _Mehhhhh_

Start by reading the linked Emotion CSS prop and styled-components CSS prop documentation to understand the requested behavior. The issue does not name repository files, tests, or an entry point, so the implementation surface remains to be determined. Done would mean agreeing on the CSS prop behavior and implementing it consistently with the project's existing styling approach.

Written by the indexing model from the issue text.