As a MFS user rather than aircraft/gauge designer, I hope those who are clever enough to make MFS gauges won't mind a comment from someone who spent his flying career looking at real attitude indicators (AI).

Ball type gyro-driven AI and their computer-generated glass cockpit equivalents have a different colour background for sky and ground.   So everything above zero degrees attitude is sky colour and everything below that is ground colour round to 180 degrees where sky begins again.

Many of the AI's on downloaded MFS military gauges that I've looked at recently have changed colour at 90 degrees of pitch.  This is not the way it works in the real world.

Thought you'd like to know!