I want to produce a custom theme. I understand how to set built-in faces, like
font-lock-nnn ones, modeline, etc.
I wonder if I can provide colors for faces that are defined by other packages, e.g. by magit, or by js2. (Inheritance helps but does not suffice.)
I suppose that a theme file can just define a function, and I could invoke it depending on presence of certain faces / variables some time later, but it looks like a hack, and won't work with normal customizations done via