"A massive dark sci-fi castle with ...

"A massive dark sci-fi castle with medieval undertones, HOLLOW SHELL ONLY — completely empty inside, no floors, no furniture, no interior walls, just the exterior structure and roof. Do not generate any interior details or rooms — leave the entire inside as open empty space. In front of the castle, build a full defensive outer wall enclosing a huge courtyard, with a large rigid gate/gatehouse entrance at the front. Walls should be asymmetrical and imperfect — uneven heights, irregular spacing between towers, no mirrored symmetry, battle-worn and weathered rather than clean or polished. Style: dark gothic sci-fi fortress, black/grey/dark stone, sharp angular towers, narrow slit windows, industrial/mechanical details mixed with medieval stonework. Block palette (mix these, no single block do