This example demonstrates a React + D3 visualization starter template, displaying a blank SVG canvas with gray and light-gray rectangles that highlight the margin convention. The code loads remote JSON data via `d3.json` but does not yet render it, focusing instead on the boilerplate structure. A `VizContainer` component abstracts the SVG and group elements, using the margin convention to position inner content. The visualization relies on React 16 and D3 v6 loaded via CDN, with SVG rendering for the output.