Start with Powder Blue on the walls. It is the kind of soft, airy blue that quiets a room down, which is exactly what you want when you sit there to think and work. It has just enough gray in it to feel grown-up rather than nursery-sweet, and it reflects daylight in a way that keeps a home office feeling open and clear-headed. On every wall it sets a calm, focused mood the moment you walk in.
To keep that softness crisp, run Soft White on the trim, doors, and any built-in shelving. It is a warm white, so it frames the blue cleanly without that stark, glary edge a pure white can give. Then bring in Navy as your accent, the deep, steady note that anchors the whole scheme. Use it on one feature wall, a painted bookcase back, or a desk nook. Powder Blue on the walls, Soft White on the trim, Navy on the one thing you want your eye to land on.