Fix Facets Overview in colab dark mode

[jameswex]

In colab dark mode, Overview looks bad because parts of it are responsive to the theme but not every visual element.

[sunishsheth2009]

Hey, I was wondering if we have a solution for this already? If not, is there an update on when it would be available or is it ok to contribute this? Thank you :)

[jameswex]

We aren't actively developing Facets so there is no update. If you do have a solution that will keep it looking the same normally but allows some dark-mode coloring, we could review it and possibly get it submitted though.