@dfs ,
We could go a step further and lament that it would be nice if the entire graphical environment of NP++ could be contained in one dialog setting, and then when we switched between Light or Dark, the environment would change all the UI references:
Settings->Preferences...->Dark Mode,
Settings->Style Configurator...->Style:, and the
Settings->Style Configurator...->Select theme:
…could be coordinated to make just switching between Dark Mode and Light Mode change them all, accordingly. As it is, I’m glad to have just found out that the Dark and Light language files can automatically change by setting that one switch in the dark mode file @PeterJones mentioned, and that automatically chooses the correct code coloring file for the environment (Dark/Light) chosen.