Contributing themes

A theme is a grammar pack: mark form, axes, legend policy, typeface, plot chrome, padding. Hex is one column — never the whole theme. Site light/dark mode is unrelated.

Do not invent a seventh chart type. Do not pull a chart runtime into packages/ or apps/.

Layout

Add a pack under packages/themes/<id>/:

packages/themes/<id>/
  theme.ts          # token table (same keys as folio)
  README.md         # intent + fence id
  examples/         # ≥ bar, line, pie fences with theme: <id>

Steps

1. Implement theme.ts with the same ThemeTokens keys as packages/themes/folio/theme.ts. No vendor chart deps.
2. Register the pack in packages/themes/registry.ts (themeRegistry + package exports). Missing packs fail loudly via resolveThemePack.
3. Add the id to THEMES in @markvis/ir so the parser accepts the fence string. Omit → folio. Unknown → E_UNKNOWN_THEME plus table fallback — never a silent swap.
4. Wire Play / Examples labels separately; this package is token truth only.
5. Keep snapshots under examples/out/themes/ green when visuals change on purpose (UPDATE_SNAPSHOTS=1).

@markvis/render-svg imports the registry only. Public fence field:

type: bar
theme: folio
title: Feb led Q3 at 180
x: month
y: revenue

month,revenue
Jan,120
Feb,180
Mar,150

Allowed today: folio · highcharts · shadcn · docs · ant · recharts. See Themes for grammar vs palette.