Prompt: A futuristic style illustration of an ancient alien citadel perched atop a rugged misty mountain peak, constructed of towering crystal spires that refract the radiant colors of twin setting nebulae, vegetated ramparts covered in bioluminescent vines glow in shades of teal and purple, flying shuttlecraft glide among the ethereal architecture which seems partly organic, partly crystalline structures, in the retro-futuristic progressive rock album cover style of Roger Dean, richly detailed linework, atmospheric colors and lighting that glow like a dream, signed limited edition print suitable for framing, highest resolution digital files.