frontend-components

Mandatory coding standards for building and refactoring any UI that has repeated structure — landing pages, marketing sites, dashboards, component libraries, any page where a pattern appears more than twice. Use BEFORE writing a new page/section/widget, and ALWAYS when you notice yourself copy-pasting markup, tuning the same thing in several places, or about to assert toContain('some copy') in a test. Enforces extract-don't-duplicate, central control (tokens + content data), behavior-preserving refactors, and behavioral-only tests (no string-matching theater). Framework-agnostic (Astro, React, Svelte, Vue, plain HTML).