frontend

# Frontend

This file is a router, not a rulebook. The rules live in four rulesets under `references/`, and reading them is the work, not the preamble to it. Before touching any file, name the references the request routes to and the one reason each is needed, then read exactly those. Declaring the set first is what makes the choice reviewable: a reference you never named is one you decided to skip, and a reference you named but never opened is a gap you still owe. Freestyling past the routed set produces the generic AI-slop output this skill exists to prevent.

**The bar is not clean-and-correct — it is work a senior designer at Linear, Stripe, or Supabase would ship.** Correct-but-flat is a failure, not a finish. Protect the surface as hard as you protect the build: design is a first-class deliverable, not a one-shot decision you lock and walk away from.

## Phase 0 — Route (before any UI work)

| Request involves… | Read |
|---|---|
| ANY UI implementation, styling, redesign, mockup, or visual decision | `references/design/README.md` FIRST. It enforces two mandatory gates — the Design System Gate (a `DESIGN.md` must exist before any component is written) and the React Dev Tooling Gate (react-grab / react-scan / react-doctor installed by default) — then routes to the taste and brand references below. |
| Spatial structure — app shells, scroll ownership, "what goes where", "this layout breaks at X" | ALSO `references/design/layout-skill.md` for the mechanics, then `references/design/stylegallery.md` to fetch a named pattern contract for that exact spatial problem. Both stack on the style skill and add no visual direction. |
| Paged output — a PDF report, a print stylesheet, a headless-Chrome print pipeline, an HTML deck printed to paper, or any "why is this page half empty" break defect | ALSO `references/design/print-paged-media.md` for the page box, the fragmentation properties, the atomic-block set, and the keep-together side effect that strands a block on a near-empty page. It adds no visual direction and stacks on the routed style skill. |
| Interaction or motion work — micro-interactions, animated components, transitions, gestures, hover/press/state feedback, "make it feel alive" | ALSO `references/design/interaction-skill.md`. The beui.dev catalog is the mandatory interaction reference: find the nearest pattern, read its real source through the file's curl recipe, and adapt the mechanism to `DESIGN.md` motion tokens. It stacks on the routed style skill — never replaces it. |
| Writing or modifying frontend code, OR auditing performance / SEO / accessibility / quality | ALSO `references/perfection/README.md`. Lighthouse 100 in every category, measured on real Playwright Chromium (never the `lighthouse` CLI), achieved through architecture — never by dropping animations or hiding content. |
| Looking up a concrete style, palette, font pairing, chart type, landing structure, or UX guideline — or generating a design system from keywords | `references/ui-ux-db/README.md`. A searchable CSV database with a CLI: a lookup tool, not a posture. `design` stays the source of truth for taste and the `DESIGN.md` contract. |
| ANY implementation or redesign that creates or updates `DESIGN.md` — plus explicit operating-layer asks (personas, critique, debt, handoff, synthetic user testing) | `references/designpowers/README.md` + `lane-c-review.md`. lane-c is the Phase Final flatness/critique reviewer and fills the accessibility-constraint and accepted-debt sections `DESIGN.md` requires. Load other lanes only when their phase applies. |

**For implementation work, design + perfection load together.** Beauty with a 2 MB bundle fails; Lighthouse 100 that looks like AI slop fails. Both win or neither does.

## Design System and Component Workflow

Every implementation must choose one of these branches before UI code changes:

1. **Concrete visual reference:** the user supplied a reference — treat it as the visual contract, then handle it by kind:
   - **Static visual reference** (screenshot, generated mockup, Stitch/Imagen output, Figma export, overview, or annotated packet): load `references/design/image-to-code-skill.md` plus the relevant design/perfection files, extract the reference's exact tokens, layout geometry, copy, spacing, states, and responsive intent into `DESIGN.md`, then implement reusable primitives against that contract.
   - **Live site or URL reference** (the user names a site to clone or gives a URL): load `references/design/clone-from-url.md`. Drive a real browser and extract the runtime truth via `getComputedStyle` — tokens, layout geometry, default/hover/focus/active states, transitions and keyframes, and downloaded assets — into `DESIGN.md`, then clone-code reusable primitives against that contract.
   Final QA for both runs `/visual-qa` in reference-fidelity mode: compare the actual UI against the reference pixel-by-pixel and verify the code is an extensible design-system implementation, not a screenshot-matched one-off.
2. **Greenfield or fresh setup:** if the user gave no concrete visual reference, design research is a build step with named deliverables — not exploration to be budgeted. Exploration-stop instincts ("enough exploration", two-wave caps) do not apply here. Fire every research lane IN PARALLEL before `DESIGN.md` is written, and open `DESIGN.md` with a `## 0. Research Log` section recording each lane's deliverable — a lane with no Research Log line did not run. Skip a lane only when its tool or network is genuinely unavailable, and name the skip in `DESIGN.md`:
   - **Embedded references:** use `references/design/_INDEX.md` to shortlist 2-3 plausible Layer B references, then read exactly one Layer A style skill and one Layer B reference in full — every line, no partial reads (they are 200-500 lines; a sliced read produces the flattened token set this gate exists to prevent). Log the shortlist, the pick, and why. Use `open-design` only when the curated set has no f