A colossal underground geothermal bathing complex built into volcanic rock, terraced hot spring pools glowing with soft amber bioluminescence, stone lanterns casting warm light across misty pathways, women in simple cotton robes soaking in steamy waters, hand-painted watercolor textures with visible brushstrokes, dramatic upward perspective through natural rock openings, volumetric steam rising from thermal pools, Studio Ghibli aesthetic with paper grain overlay, cozy winter atmosphere, deep obsidian volcanic stone and warm amber lantern glow palette, rendering: raytracing global illumination volumetric lighting PBR materials