The short answer to “there are no pure CSS chart libraries that can generate radar/spider charts” is: there is one now. And it did not get heavy to do it.

st-core.fscss v2 draws area, line, and spider/radar charts with the same idea:

FSCSS @arr for data

CSS custom properties for coordinates

clip-path: polygon() for shapes

Gradients for grid / spokes

No SVG. No canvas. No Chart.js / D3 / Recharts on the critical path.

The claim this answers

For a long time the pragmatic take was:

Pure CSS can fake a bar or a simple line. Radar needs polar math, multiple series, spokes, labels — so you need SVG or a library.

That was fair when “CSS charts” meant hand-written polygons or one-off hacks.

st-core@v2 treats radar the same way it treats linear charts: data in → variables out → polygons on screen .…