Act as a seasoned xenobiologist with expertise in extreme-environment adaptations. Design a sentient civilization that has evolved to thrive on the surface of a [COLOR] gas giant with [ATMOSPHERIC COMPOSITION]. Describe their: 1) Physical adaptations for floating in dense atmosphere (e.g., gas bladders, streamlined bodies), 2) Unique sensory organs to perceive their environment (e.g., electromagnetic field detection, pressure wave receptors), and 3) Social structures shaped by their three-dimensional habitat (e.g., floating hive cities, migration patterns). Include how they harness energy from [LOCAL ENERGY SOURCE] and what forms their technology takes when traditional solid materials are scarce. Consider how their perception of 'up' and 'down' differs from terrestrial beings.