Create a seamless vector pattern that captures the essence of fog in an urban environment. The design should feature abstract silhouettes of city buildings and streetlights, softly blended into a gradient background that transitions from light gray to deep blue, mimicking the appearance of fog rolling through the streets. Incorporate subtle textures that suggest the softness of fog, using smooth curves and flowing lines to create a sense of movement. This pattern should be versatile enough for use in textiles or wallpapers, evoking a serene and mystical atmosphere that invites exploration of the city.