How to Style a Custom Input Component?

What is the best way to style a custom input component? Can I use something like BASEUI or even styled components? The example in the docs is just using normal css?

We're working on improving this story right now, actually! https://www.sanity.io/blog/streamline-your-studio-development-with-sanity-ui
We're still missing some reusable building blocks, but this is at least the
direction we're going.