Denim is the most comfortable blue there is, and that ease translates straight to a bedroom. Faded denim on the walls feels worn-in and relaxed, a medium blue with a touch of gray that never reads loud or juvenile. It is the kind of color you settle into rather than notice.
A soft white on the trim and ceiling keeps the edges clean and bright, while a soft gray offers a quiet option for an accent wall or built-in without breaking the calm. Warm wood through the floor, a headboard, or a nightstand is what really makes the room feel cozy, balancing the cool blue with something earthy and grounded. The whole palette is low-contrast on purpose — nothing here demands attention, which is exactly what you want in a space built for rest.