This example presents a stacked bar chart illustrating population distribution across age brackets for several U.S. states, with each bar segmented by age group and colored using a categorical scale. The visualization is rendered as an SVG using D3.js (v3.5), with population values loaded from a local CSV file. Users can hover over individual bar segments to see a tooltip displaying the specific age group and its population count. The chart sorts states by total population and includes axis labels, demonstrating D3's core APIs for data binding, scales, and SVG rendering.