Consider adding non-markdown elements to Styled

[jxnblk]

Some HTML elements might be expected to exist in the Styled components, e.g. Styled.button, but don't currently. It's probably not harmful to add a few more common elements to the mix.

[connorholyday]

This idea makes sense to me as I'm using theme-ui for both HTML (landing page) and markdown (blog). Adding all of my base elements to the theme config keeps things nice and tidy without having to look-up which elements markdown doesn't support - or double checking my variants for those extra elements. Then markdown can pick up all of the Styled components it needs and I have one section for all of my base elements.

Is it as simple as updating the tags array here?

[jxnblk]

Yes, but we'll want to still limit which tags we add here since they'll increase the overall bundle size and cannot be tree-shaken

[connorholyday]

I see! Forgive me if this is a silly question, but could these extra non-markdown elements be generated by mapping over the theme.styles keys? Thinking along the lines of letting people define what they need up-front via the theme config

[jxnblk]

I guess they could be created based on theme.styles, but that would probably require creating components during render, which is generally not good for performance

[connorholyday]

Oh okay that's interesting, in that case is using variants different from creating components during render? (have you got any links where I can read more about this?)

As for element suggestions, how about the base form elements: form, label, and input

[jxnblk]

There are some docs here, but they certainly could use some work: https://theme-ui.com/guides/variants

Variants use the theming context available in the sx prop to add the styles, so it's a bit different from creating a React component. As far as which elements, you could start a PR for discussion, if you're interested in taking a stab at it