This example presents a fixed, full-window visualization of seven semi-transparent circles, each with a distinct neon color and position defined by explicit x, y, and radius values. It uses the d3.select and d3.join API from D3 version 7 to declaratively create the SVG container and circle elements, applying attributes for size, fill, and opacity. The static layout derives its dimensions from the container’s clientWidth and clientHeight, and the circles are drawn over a light green background.