A little. Assuming you are talking about the colors shown on the "politcal map" (the middle button between the "terrein map" and the "economic map") colorscales.csv in the Map folder can be tweaked. I think fantasy scenarios might be a problem in terms of colors used. Also, not all countries colors are handled out of this file (wierd). Robo did some original research, and the IGC adopted part of his change. I did more changes which I think are quite nice.
Some of the colors in colorscales.csv are used for other game features, though, so some care is required.
Here are my changes (from a post in
http://www.europa-universalis.com/forum/showthread.php?threadid=8278&highlight=color )
BTW, I'm referring to the "political map" when "diplomacy screen" is mentioned in the following.
Dark grey countries on diplomacy screen. A bit too dark.
- lightened a bit
grey;;;
red;green;blue;index
195;195;195;0
145;145;145;15
70;70;70;40
100;100;100;64
Dark brown countries on diplomacy screen. Way to dark.
- made a burgundy-red'ish
- magenta'ish in Robo's original version
dark brown;;;
red;green;blue;index
255;0;64;0
220;0;64;10
180;0;64;24
76;0;64;64
Orange countries on diplomacy screen. Way to bright and unfortunately positioned.
- made a dark green-blue
- cyan in Robo's original version
light orange;;;
red;green;blue;index
0;180;150;0
0;150;125;10
0;120;100;24
0;70;60;64
Russia on diplomacy screen and Orthodox religion on Religion screen. Too dark.
- much lighter.
brown;;;
red;green;blue;index
240;240;170;0
180;160;100;20
120;80;30;50
90;60;10;64
I especially like the Russia change. But, of course, everybody has their own likes.
