Spinning Globe with capitals
A spinning globe displays capital cities as proportional points, with land, water, graticules, the equator, and the prime meridian rendered in gradient colors that shift with the rotating orthographic projection. Using d3-geo’s `geoPath` and `geoOrthographic`, the animation advances longitude each frame via `requestAnimationFrame`, while city radius scales with square-rooted population data from a reduced world cities CSV. Overlaid graticule lines and country borders are clipped to the globe’s visible hemisphere, producing a stylized, night-side gradient effect.