Great idea, using it now! You can also apply styles with uBlockOrigin, for example the equivalent uBO rule is: news.ycombinator.com##html:style(filter:invert(100%); background = #fff;) Setting topcolor to 0099ff (blue) in the profile settings returns it to its glorious orange state after color inversion.
For future reference, we can recover the orange colors by adding a hue-rotate filter too. Here's my current rule:
news.ycombinator.com##html:style(filter:invert(100%) hue-rotate(180deg))
news.ycombinator.com##body:style(background: white)