In Theming documentation, specify which components are unable to have custom appearances and sizes

[jasonbarry]

https://evergreen.segment.com/introduction/theming

appearances: These are the custom styles that you can apply to a component based on the appearance prop. Note that some components don't have this.

Which ones? Why not?

sizes: These are additional props that you can alias via a size property. Again, note that some components don't have this, and you can only configure baseStyle.

Which components?

[Jittojoyes98]

Anyone working on this issue?

[brandongregoryscott]

Hey @jasonbarry,

Thanks for raising this issue. We've heard from people a lot recently that the theming documentation could be improved, so I opened up a discussion (#1597) to request more specific feedback on where we should be doing 😄

Specifically, there's not a lot of rhyme or reason to why certain components support appearances, what parts of each component are themeable, etc. I think the doc site will need some infrastructure setup to add a "Theming" tab to each component's detail page, similar to the Props table. Ideally this could also read from the component's theme code to provide guidance and reduce the amount of content we need to write for each.