This example demonstrates a blank React + D3 visualization starter template, displaying only the SVG container structure with visible margins highlighted in gray. The `VizContainer` component abstracts SVG and group elements following D3’s margin convention, rendering an outer and inner rectangle to visualize the layout. Built with React 16 and D3 v6, the code uses CDN-loaded libraries and a `showMargins` prop to toggle the rectangles, providing a clean foundation for adding custom charts.