Changing colours

How can I change the colour of my team?

Edit these 3 files (it's pretty self-explanatory if you take the time to look at them):

Civ 4/assets/xml/civilizations/Civ4CivilizationInfos.xml
Civ 4/assets/xml/interface/Civ4ColorVals.xml
Civ 4/assets/xml/interface/Civ4PlayersColorInfos.xml

make a copy of each of these files and place them in your custom assets folder, then edit them.

you can even create your own custom colors.