Create a striking flat design illustration of a nighttime cityscape enveloped in fog, capturing the enchanting atmosphere of an urban environment after dark. The artwork should feature simplified geometric shapes representing buildings, skyscrapers, and streetlights, all rendered in a bold, contrasting color palette of deep blues, purples, and soft yellows. The fog should be depicted using smooth gradients and translucent overlays that gently obscure the lower parts of the structures, creating a sense of depth and mystery. Incorporate stylized elements like clouds and stars peeking through the fog, along with minimalist silhouettes of people walking or biking, to add life and movement to the scene. The overall composition should evoke a sense of wonder and tranquility, inviting viewers to explore the beauty of this foggy nighttime cityscape. Keywords: "flat design," "foggy nighttime cityscape," "urban atmosphere," "stylized silhouettes."