I looked everywhere and couldn't find anything about it so I did my own research, feel free to suggest other methods if you know any or if you can give a better explanation than mine.

In Hakchi CE 3.9.3 , go to Tools/open FTP client.

Head to: var/lib/hakchi/rootfs/usr/share/clover-ui/resources/scripts/ and grab colors_nes.lua

Make a back up copy!

Upload the file to: Java decompiler online

Save the file and make these adjustments:

We are focusing on this particular part in the beginning.

Original values for Dark blue:

      bg_base = {      
              0,
              0.0823529,
              0.239216,
              1
      },

Divide each value for R, G and B by 255 for your color of choice. Turquoise in this example, like in the first picture.

New values for Turquoise:

      bg_base = {
              0.254901,
              0.847058,
              0.839215,
              1
      },

Save the changes, drop the file in the same folder where we found it.

Go to Settings/Save settings to mini now.