ko-Z Browser Theme nga Faceman

A dark theme based on the colors from niivu's ko-z theme for Windows 10.

https://www.deviantart.com/niivu/art/ko-Z-for-Windows-10-842117943

The general style also fits very well with Gnome-based desktops using the Yaru dark theme.

This theme is works well with the current UI but was originally intended to be used with the "Photon" design language, which can be restored with black7375's Firefox UI fix: https://github.com/a/Firefox-UI-Fix