I actually really like the combination of blue and cyan. To me, they aren't two shades of the same color, but different hues altogether, and have quite different symbols and associations. Here's the flag of the Republic of Arctica, a sparsely-populated but resource rich state occupying the eponymous island in the middle of the Acidalian Ocean near the Martian north pole. The capital, Chelomey, is a small city of 200,000 centered around the seaport, which serves as a hub for transportation all across Mars' northern hemisphere. Some small scale agriculture of potato, broccoli, cabbage, and strawberry occurs on the surface during the summer weeks in the southernmost reaches of the the southwards-facing peninsula on which Chelomey is located, but most occurs underground in fission-heated bunkers and most of the food is imported anyway. Most of the economic activities of the hinterland revolve around mining of uranium, iron, copper, niobium, potassium, and aluminium, and nuclear-heated mining communities are connected by railways stretching across the ice. Whaling and sealing occur off the coast as well as fishing of shrimp, shark, halibut, haddock, cod, and Chryse Nelma. The deep blue represents the Acidalian Ocean, the cyan represents the sky, the white represents the clouds, and the two crescents represent Phobos and Deimos.