What problem does it solve? When migrating a legacy page to a new frontend, developers often guess at styling values from stale committed CSS. This Skill captures the live legacy render's per-element computed styles as an authoritative answer key, so code generation reproduces real values instead of eyeballed approximations. ## Core Features & Use Cases - Live Style Extraction: Runs a Playwright probe against the live legacy page to record per-element computed styles, asset inventory, and markup structure into style-spec.json. - Source Fallback Cascade: Falls back to source-derived values when the legacy URL is unreachable, flagging them so downstream parity checks know the provenance. - State Machine Safety: Refuses to run on flipped, done, or flip-in-flight pages and warns before demoting verified pages, keeping the migration tracker consistent. - Use Case: After analyzing a legacy hotel booking page with fm-analyze, run this Skill to capture its exact computed styles so fm-plan and fm-gen can rebuild the page pixel-faithfully and fm-parity can later re-probe the same truth source. ## Quick Start Run /frontend-migration-plugin:fm-style-spec for the analyzed page, optionally passing --app and --legacy-url, to generate its style-spec.json before planning.
