This example demonstrates the visual difference between an SVG shape with an explicit `fill="red"` attribute and one relying on the default black fill, both as identical circles. Two overlapping `<circle>` elements are placed in an inline SVG within a minimal HTML page. No JavaScript or external libraries are used; the rendering relies purely on SVG’s built-in presentation attributes and the browser’s default styling. The example highlights how explicit CSS or attribute values override the default styling.