System Settings : Customize and Brand Rev : Use a Custom Primary Color for Rev
  
Use a Custom Primary Color for Rev
A custom primary color may be used to replace the default black background color in the top menu bar and header. It will also replace the color of the Video screen background.
*To use a custom primary color:
1. Navigate to Admin > System Settings > Branding.
2. Click the Primary Color color picker in the Colors section and choose a custom primary color. You may also enter a Hexadecimal value.
3. Click the Save Changes button to apply the new primary color.
4. Click the Reset Default button to revert back to the default primary color.
As noted, the custom color replaces the default black background color in the top menu bar, header, and the back of the Video Player background.