Are paddings/margins documented somewhere?

[wsw70]

^{(also asked at https://community.home-assistant.io/t/custom-button-card-are-paddings-margins-documented-somewhere/952553)}

I am just starting with custom:button-card and after some very basic configuration I have this test card:

I now would like to modify the style, especially the spacing (some examples above in the image - these are just examples to set the idea). The closest I found in the documentation is https://custom-cards.github.io/button-card/stable/advanced/styling/#advanced-styling-options but it is still too much of a high level.

Is there a place I should look into? Or a naming condition for elements or classes, I could address in the styling? Or should I dig into the code?