The style property settings for Question & Answer Forums can be found by navigating to ACP → Appearance → Style properties → [TH] Question & Answer Forums.
The options under Settings allow you to:
Set the positive and negative color.
Enter the FontAwesome icon you would like for the best answer toggle icon, answer up vote icon, answer down vote icon, thread list question indicator icon, and thread list question indicator icon (answered).
The settings below allow you to change the coloring and fonts:
Best answer button
Best answer button (selected)
Vote button (voted)
Vote count (positive)
Vote count (negative)
Best answer post styling