Native support for light/dark mode based on `prefers-color-scheme`

It could be nice if the default basemap and styling changed whether the user is in light mode/dark mode.

I was reading https://deck.gl/docs/api-reference/widgets/overview which mentions how it's possible for the deck.gl widgets to switch their light/dark mode

It looks like `prefers-color-scheme` isn't able to read from the current vscode theme, but if vscode is set up to change light/dark themes based on the OS, then it'll still match.