This example demonstrates how to select, filter, and style SVG circle elements using D3 v7. The page shows a row of five circles rendered inside an SVG container, with every other circle filled orange via `selectAll("circle").filter()`. The code also includes commented-out demonstrations of `append()`, `remove()`, and `each()` for adding text, deleting elements, and applying conditional styling. Data is not loaded externally; instead, the circles are predefined in the HTML markup and manipulated directly through D3 selection methods.