This example shows a grouped bar chart with 10 sample categories and 5 series, where each bar height represents a random value between 0 and 1. The visualization uses D3 v4 with SVG rendering, employing `d3.scaleBand` for both the outer category bands and inner series bands, `d3.scaleLinear` for the y-axis, and `d3.scaleOrdinal` to assign a categorical color palette. Data is generated inline using `d3.range` and `Math.random`, with the axes styled via CSS and the chart drawn as nested groups of rectangles translated along the x-axis.