kingdom colour?

They are hexadecimal RGB colour codes converted to decimal numbers. For example, a light yellow colour has these RGB values:

Red: 255
Green: 236
Blue: 139

The hexadecimal code for this colour is: FFEC8B
Convert that to decimal: 16772235

The number 16772235 is what has to be put into the txt files in this example.

IMPORTANT!!!

You also need to replace the same colour code (16711680) in Scripts.txt, under the line activate_player_faction -1, or else you risk getting the vanilla red colour after all!

The above fix only worked for me the first time. I then joined another faction again because I wasn't ready for my own Kingdom yet, and then when I was ready and rebelled again, I got the red colour. So I kept searching until I found this fix.