Minimalist architectural rendering, clean lines, negative space, subtle gradients. Envision a utopian eco-city floating above the clouds. Sleek, organic structures curve and intersect, their white surfaces punctuated by lush vertical gardens. Solar sails shimmer in the sunlight, while wind turbines spin lazily in the breeze. A network of transparent tubes connects the various levels, with tiny figures visible inside. The composition should emphasize harmony and balance, using careful placement of elements to guide the eye and create a sense of serene futurism.