This interactive world map highlights countries by name on hover and changes their fill color when clicked, toggling between red and light green with a one-second transition. Built with D3 v5 and TopoJSON, it loads world-atlas geographic data, renders shapes using `d3.geoPath` with a Natural Earth projection, and includes a pan-and-zoom interaction via `d3.zoom`. Hover styling is defined in CSS, while click behavior is handled by appended SVG paths with `d3.select` and `transition().duration()`.