A serene contemporary spa bathroom at twilight, freestanding curved white stone bathtub overlooking a private courtyard with flickering candlelight, massive frameless windows with sheer linen curtains, pale terrazzo floors with brass inlays, hanging dried botanical arrangements, a weathered wooden stool with folded towels, hand-painted watercolor textures with visible brushstrokes and paper grain, cool sage and warm ivory color palette, Unreal Engine 5 cinematic render with frame-by-frame oil painting aesthetics, gouache background with subtle texture, cinematic depth of field, candlelight casting dancing shadows across textured walls, global illumination creating ethereal atmosphere, architectural digest quality composition, contemplative sanctuary mood at dusk in private wellness retreat