This stacked bar chart shows the percentage of device usage (Mobile, Laptop, Tablet, TV) across five age groups, from 10-20 to 51+. The visualization uses D3 v7 with `d3.scaleOrdinal` for color encoding, `d3.scaleLinear` for the percentage x-axis, and `d3.scaleBand` for the age-group y-axis. Interactive tooltips appear on hover via the `mouseover`, `mousemove`, and `mouseout` events, displaying the exact percentage for each device segment. Data is loaded from a CSV file, and the chart is rendered as an SVG with a legend positioned to the right.