D3 Data Visualization Overview Use this skill for custom browser visualizations where SVG or DOM semantics matter and a declarative grammar no longer fits cleanly. D3 is strongest when the chart needs bespoke scales, marks, layouts, transitions, zooming, brushing, annotations, or vector export. Default assumption: use D3 for scales, layouts, geometry, labels, annotation layers, and behavior. Do not turn D3 into the entire application architecture if a framework already owns the surrounding UI. Choose D3 When - the chart needs custom marks or nonstandard layouts - SVG quality matters for expor…