This example demonstrates the use of SVG fundamentals by rendering a circle and an ellipse directly in an HTML page, styled with CSS and JavaScript. It showcases how SVG elements like `<circle>` and `<ellipse>` are drawn using the `viewBox`, `cx`, `cy`, `r`, `rx`, and `ry` attributes, with inline styles defining stroke and fill colors. The code uses no external libraries, relying solely on native SVG, CSS, and JavaScript to illustrate basic vector graphics in a browser.