This example demonstrates a minimal HTML page that sets up an SVG canvas for data visualization. It initializes a fixed-width and fixed-height SVG, applies margins to create a plot region, and defines quantitative scales for x, y, radius, and color using d3.scaleLinear, d3.scaleSqrt, and d3.scaleDiverging with the RdYlGn interpolator. The scales establish ranges for axes and encode data attributes, though no data is plotted. The code imports D3 v5 and the d3-legend library for potential legend rendering.