A high-quality anime illustration featuring a detailed cross-section view of a deep underground facility, presented as a vertical architectural diagram. The image is composed as a wide shot looking sideways through the earth's layers, showing multiple subterranean levels descending deep into the ground. Clear horizontal demarcations label the floors from top to bottom: "B10F", "B15F", "B20F", and "B30F", with the lowest level designated as a "Safe Zone" (安全圏), indicated by reinforced walls and cozy living quarters. Each floor contains minute details of industrial piping, concrete supports, mechanical rooms, and small living spaces. The surrounding earth is rendered with various geological textures, including dark soil, grey rock strata, and glowing mineral veins. The lighting is artificial and moody, with flickering fluorescent lamps casting cool blue and sterile white glows within the corridors, contrasted by the oppressive darkness of the deep underground. The atmosphere is claustrophobic yet organized, conveying a sense of subterranean isolation and strategic depth.