How to decorate a small bedroom without windows? In order not to make the whole room look dark and stuffy.

Unless absolutely necessary, a room without windows (called darkroom in architectural design) is not suitable as a bedroom, but can be used as a study.

Design the right wall surface from the part above the bed surface (generally 400~500mm) into light-transmitting materials, such as frosted glass, embossed glass, etched glass, glass brick, etc., so as to realize lighting. On the one hand, you can borrow the natural light in the direction of the living room, on the other hand, you can avoid line of sight interference.

The ventilation problem may be that the top section of the right glass wall can be designed as a grille or louver, which will make the ventilation better, but there will be noise influence, that is, the sound of the living room will affect the users in the room.