This example demonstrates SVG fundamentals with two circles rendered inline in an HTML document. The first circle uses default black fill, while the second is explicitly styled with a red fill. The code directly embeds SVG elements using the `<svg>`, `<circle>`, and `fill` attribute, showing basic shape creation and styling without any JavaScript libraries. Both circles are positioned via `cx` and `cy` coordinates with a radius of 50, illustrating how SVG primitives render visually in a browser.