Architectural Minimalist Realistic Starry Sky

Create a vertical 3:4 surreal minimalist pastel digital painting. A huge sandy cave in deep indigo and blue-gray occupies the edges of the frame; the cave wall curves into a vertical irregular round-arch opening in the upper half, its silhouette resembling a soft keyhole; the left cave wall curls upward from the bottom of the frame, while the right inner wall sinks into deep blue shadow. The cave wall surface has fine, low-contrast wind-eroded ripples flowing along the curves and soft pastel grains. Beyond the opening is a calm twilight sky, transitioning from pale gray-pink to light purple-red, with only a very small white dot above center; below, three to four simplified layers of blue distant hills are stacked, lighter the farther away. In the lower part of the frame, a pale gray-white curved sand slope enters from the lower left and narrows toward the lower right; on the slope is a slender adult facing away from the viewer, wearing a dark long coat and dark trousers, walking toward the opening, the hem of the coat drifting slightly to the side and back; behind them remains a trail of dark footprints that decrease from large to small with natural spacing. The figure is very small, and the cave scale is enormous. Use restrained large color blocks, soft pastel washes, paper-like fine grain, and slightly imperfect edges; do not apply realistic sharpening; do not add a starry sky, plants, architecture, text, borders, third-party logos, or watermarks.