Automatic Light/Dark Theme from prefers-color-scheme

The light and dark themes, as they exist currently, are wonderful. However, for those of us who set our theme dynamically, it is frustrating to have to manually adjust the theme in settings whenever the sun (dis)appears.

It would be wonderful if we could add an Automatic (Light/Dark) theme that utilizes either some media queries in CSS for prefers-color-scheme or, if that's not possible, even some client-side JS.

More than happy to help implement this, would just need some pointers as to where to start.