Changing Color of Flash Screen Before Lesson

Hi everyone! How do you change the color of the screen that flashes before the lesson loads on the screen when you either review it in 360 or when it loads in an LMS? I changed the player screens to match the new colors my client wants but can't seem to figure out why. In the attached example, you can see when I click on it, it flashes a dark blue color then goes to the black background from the player. It does this when it is loaded into an LMS as well. Ty!