This example demonstrates a minimal React application that renders a single yellow circle with a black border onto a blank page. The visualization uses a reusable `BackgroundCircle` component, which accepts `radius` and `strokeWidth` props to define the circle’s size and outline. The app is built with React 16.9 and ReactDOM, which mounts the component into a root div, with styling that hides page overflow. The code does not include any data or interactive features, focusing solely on the basic wiring of a React component for a fixed graphic.