Adding dark mode

At the risk of losing a lot of nerd cred: I, by and large, prefer light mode. But I'm not dogmatic about it.

Media queries make it very easy to detect the readers preference and CSS custom properties help keeping the rest of the styling clean and non-repetitive. So I thought it would be a right neighbourly thing to add the following:

It looks plausible to me, but visual design isn't my strongest suit. So if someone, who prefers dark mode, has thoughts on it, I'd be thrilled to hear from you.