[bookivore]

Thanks. So, in short, it can't be done with Sigil - even though setting background color IS respected, setting foreground color is NOT, not even with "! important". I'll make a feature suggestion when I figure out where to post it. Proofing/editing an epub in black on white is just too painful for many people, including me.

For anyone else in the same boat, I suggest making a style.qss that has the opposite colors of what you want (for example #ffff00 for a saturated blue), set the code view colors to black foreground text on white background, set Compton to invert Sigil windows & either turn Compton on at boot, or either manually or with a wrapper script the first time you need it. And on those rare occasions when you DO need to edit an epub with multicolored text, invoke sigil with a different stylesheet or no stylesheet & turn off Compton. It ain't perfect, but it is reasonably good.