Design by http://fox-petal-designs.deviantart.com/

The Federal Guard originates on a planet substantially warmer than is comfortable for most clothed parahumans, their dress uniforms were designed to be well-ventilated with this in mind. On the battlefield environmentally sealed power armor is more common, of course. In the modern era dress uniforms are made from smart fabrics that can adjust their insulation or in emergencies reconfigure into a light vacuum suit.

The colors indicate which division of the service the wearer belongs to:
Blue: Ship's crew; pilots, officers, navigators, etc.
Green: Engineers' corp; mechanical, physical, civil, and ecological.
Red: Soldiers; those who fight with handheld weapons and terrestrial vehicles. Includes both "infantry" and "marines" with no real distinction between the two.