A minimalist book cover for a science fiction novel set in the 1960s, featuring the discovery of a secret planet. The space colony is designed in the brutalist architectural style of Le Corbusier, with tall, concrete skyscrapers that have clean, angular lines. The scene includes a large but slightly smaller glowing planet in the background, casting soft light over the modernist buildings. The color palette should incorporate shades of purple, off-white, bluish blacks, and greyish blues, avoiding any warm tones. The overall design should maintain a collage-like texture, blending the futuristic architecture with the cosmic elements. collage style, textured, purpletones