Create a sleek, urban-inspired t-shirt graphic titled "London Life." The design features a minimalist outline of the iconic London skyline, prominently showcasing landmarks such as the Shard and Big Ben. The skyline should be rendered in a bold monochrome palette, with a subtle gradient effect transitioning from a lighter shade at the top to a darker shade at the bottom, adding depth and dimension to the outline. The text "London Life" should be integrated at the bottom of the design in a bold, sans-serif font, centered for a modern look that complements the skyline graphic. Utilize digital illustration techniques to create vector art with smooth lines and gradient overlays. The final design should maintain a transparent background, making it perfect for casual wear and as a thoughtful gift for anyone who loves the city.