Create a captivating flat design illustration of a street scene in a city, enveloped in fog. The image should showcase simplified buildings, cars, and pedestrians, all rendered in bold colors and geometric shapes. The fog should be represented with soft gradients and translucent overlays, creating a sense of depth and obscuring some details while allowing others to stand out. Incorporate elements like streetlights and trees, designed in a minimalist style, to enhance the urban environment. The overall composition should evoke a sense of movement and life, with the fog adding an element of intrigue to the bustling city scene. Keywords: "flat design," "foggy street scene," "urban illustration," "intriguing atmosphere."