As night descends, the ceiling begins to breathe. With a light touch on the remote, the 270-degree starry dome gradually illuminates, accompanied by a soft light system that mimics the pulse of the Milky Way. The Big Dipper hangs directly above the bathtub, its starlight shattered and gathered again by the rippling water. At this moment, as you float in the warm water, it feels as though you are drifting through the primordial nebulae of the universe.