This bar chart visualizes the wealth of billionaires, using a sequential color scale where bar fill intensity corresponds to net worth in billions. The chart encodes value through both bar height and color, with a legend explaining the color mapping. Built with D3 v6, it loads CSV data, applies a linear color scale from white to blue, and renders SVG rectangles. The visualization uses `d3.scaleBand` for x-axis positioning and `d3.axisBottom` for ticks. A `d3.legendColor` legend clarifies the color scale. Hovering highlights each bar in red, and tooltips display exact values.