Fork of Circles with D3
This example uses D3.js to render three semi-transparent circles on a soft green SVG background. It shows how to use D3’s method chaining and the `select`, `selectAll`, and `join` functions to create and update SVG elements from a hard-coded data array. The code measures the container’s dimensions via `clientWidth` and `clientHeight` to size the canvas, then sets each circle’s position, radius, and fill color. It demonstrates the general update pattern for idempotent rendering.