In Stellaris, my fleets' firepower amounts are listed under their location in the Outliner window in yellow. I assume this is the default font color for the UI.
However, one of my fleet's firepower label is listed in red, and there's no indicator or tooltip explaining the difference in color. I don't think the guided tutorial slave robot covered this, either.
Why is one of my fleet's firepower labels showing up as red?
To provide a bit more information, my 3rd Fleet is comprised of 14 Corvettes. My 1st Fleet, by comparison, has 12 Corvettes and 1 Cruiser. I don't recall the ship breakdown of my 2nd Fleet at the moment.
Originally, I surmised that the red color coding was because my 3rd Fleet was executing a combat order/was in combat, but I saw the red number even when the relevant fleet was not in combat or heading toward combat, which rules out that theory.