Two editor toggles under Settings › Editor › Color Scheme › Language Defaults (off by default, also actions `editor.toggleRainbowBrackets` / `editor.toggleSemanticHighlighting`):
- Semantic highlighting (IDEA's rainbow variables): locals and parameters coloured by a name hash from LSP semantic tokens; fields, statics, constants, library symbols untouched.
- Rainbow brackets (VS Code's bracket pair colorization): (), [], {} by depth, unmatched in the error colour, strings/comments skipped, visible ranges only with 4 KB checkpoints.
Palettes are theme tokens (`--syn-rainbow-1..5`, `--syn-bracket-1..3`, light/dark/high-contrast), editable in the Color Scheme tree, and mapped from IntelliJ `.icls` RAINBOW_COLOR1..5.
App verification on macOS found the colours were overridden by the syntax highlighter's span nested inside the marks; the rules now cover descendants. Verified both toggles on/off live in a TS file.
Fixes#56https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn
Per the maintainer's decision for #24, no third-party themes are bundled; instead a theme plugin template and docs let the community port themes (IntelliJ also ships few themes, the rest are plugins).
- templates/theme-plugin: manifest-only plugin with an original example (Harbor Night) covering every UI token and an editor scheme (.icls equivalent).
- docs/plugins/themes.md: format, IntelliJ / VS Code porting tables, generated token reference (pnpm gen:theme-docs); drift test fails when tokens.css and the template/reference disagree.
- pnpm theme:import-intellij: dependency-free converter for IntelliJ .theme.json (+ .icls).
- Plugin host: themes may name an editor-scheme merged over the theme; comments allowed in theme files.
- Fixes: a plugin theme's kind now switches the light/dark base; plugin themes go in their own stylesheet so the Appearance accent and editor scheme still layer on top.
Verified: ide-plugin tests, vitest (44), in-app on macOS: installed the template from disk, applied Harbor Night (dark base + teal accent over Islands Light), back to default restored the light theme.
Claude-Session: https://claude.ai/code/session_01VUYsdXA2nkF5v6zsC93dpn
l0ng-ai