So I modified Dino's dark theme a little.

Viewport background, and gridlines, and accented gridlines.

Changed the Olive (Brown) in his MoI.css, from Hex # 7C593F, to MoI5beta Hex # 885511.
There were 11 places to do this change, perfect for Notepad++ CTRL+H command.

MoI4 on left of screen, MoI5beta on right of screen, the screens are looking very similar.
There is more that could be done, but I am not going to do more at this time to Dino's dark theme, MoI4.
Dino commented a couple of the colors at the top of his MoI.CSS file.

- Brian

Using some of the tools at rapidtables, is is easy to copy paste MoI4 dark screen portion, and see the color.
Also can translate Hex # and RBG numbers easily.

https://www.rapidtables.com/web/color/color-tester.html
https://www.rapidtables.com/convert/color/index.html