Setting fill color on basic shapes using themes (.json)

Hello everyone

I am trying to create a theme using the documentation that is provided by microsoft.

Unfortunately the Docs are old and some of the methods described have deprecated over time, and other functions have been implemented, but not documented.

I got most of the theme going, but i simply can't figure out how to change the fill color of a shape.

I suspect it has to do with the fact that more shapes have been put into PBI since the documentation was written, and that the function thirdLevelElements: backgroundLight that used to decide the fill color of shapes is deprecated at this point.

I've tried looking at a old thread about this https://community.powerbi.com/t5/Desktop/Themes-For-Shapes/m-p/196835 and a github containing the functions for a shape https://github.com/deldersveld/PowerBI-ThemeTemplates/blob/master/Shape.json but to no avail.

Any help is appreciated.