昼・夕暮れ・夜を切り替えられるブラウザ3D超高層ビル都市

Build an explorable 3D city of very tall skyscrapers that runs in the browser as a single page with WebGL (Three.js). Use dark glass towers with thin neon cyan and magenta edge lines and scattered lit windows, set against a warm gradient sky that goes from amber at the horizon to violet above. Add a minimal futuristic HUD: a small title block, a time-of-day switch with Day, Sunset and Night modes, a local clock with a haze readout, a mini sector map, and buttons for changing viewpoint and travel mode. The mouse steers a camera that glides between and above the towers, so the player feels the height of the buildings. Vary tower shapes: spires, stepped tops, slanted roofs and wide slabs. Switching the time of day should change sky colour and window lighting. Done means a smooth, continuous flight through a dense skyline in all three lighting modes with the interface readable on top.