Currently I am adding a custom button into the product section. I have checked the theme documents and seems like there is no standard way to look up for typography or colors, neither how to inherit button styles from the theme.
Seems like the class names are really arbitrary, and the CSS env vars also are arbitrary depending of the theme it makes a little bit confusing how to follow this guideline.
I don't think that in the case of a button the solution is just change the CSS to inherit color/typography, because will be tied to the container that wraps the block, and could be totally different depending of where it is placed.
Then if we would like to find the elements from the theme options this will work only for 2.0 themes, and if, they are using the same base configuration file, because as I know, they could be highly customisable. I can't see an obvious way to solve this issue.