A book cover for 'O Crepúsculo da Civilização'. The cover features Valentina

A book cover for 'O Crepúsculo da Civilização'. The cover features Valentina, a young mage, seen from behind or in silhouette, with her face and skin tone hidden. She is standing in a devastated, post-apocalyptic cityscape, with ruined buildings and a dark, ominous sky. The background combines elements of futuristic technology and ancient magic, with glowing runes and broken machinery scattered around. Valentina is holding a staff or magical artifact, with a faint aura of power surrounding her. The overall mood is intense, dark, and mysterious, hinting at the epic struggle and the clash of magic and technology. The title 'O Crepúsculo da Civilização' is prominently displayed at the top or center, with a strong, bold font that reflects the gravity of the story.