A circle tracks the user’s cursor across a full-screen SVG canvas, updating its center position in real time. Built with React 16.9 and SVG, the component uses the `useState` hook to store mouse coordinates and `useCallback` with an `onMouseMove` handler to capture `clientX` and `clientY` events. The circle’s `cx` and `cy` attributes are bound to this state, causing a smooth, reactive movement that mirrors the pointer exactly.