Nature of color edit dialogs
The color edit fields look like this:
If you press the down arrow it will give a palette map to choose from and you can expand this map by clicking "More Colors" as shown below:
It will display this dialog window which you should already be familiar with because it is in many applications:
This will allow you to customize your colors to fine tune them. After setting all the colors, I recommed that you save this group of color settings as a Color Theme.