:root {
  color-scheme: light dark;
  --text: light-dark(#000, #FFF);
  --bg: light-dark(#EEE, #242936);
}

Hmm, I guess the advantage of that over

@media (prefers-color-scheme: dark) {
    /*set different values for variables*/
}

is that you can set the color scheme via a button much more easily then.

Had to think about that for a moment, because the old way of doing things seemed fine, but that is a pretty good reason, I guess.