design system alignment across app and website

This release aligns both surfaces with the new typography-first design system.

Web app

Website

This change keeps both products visually related while preserving their different jobs.

Follow-up: search and shortcut updates landed later in global article search and updated keyboard shortcuts.

Follow-up (2026-02-11): security and reliability hardening is now standard platform behavior: Manual refresh only (background jobs deferred), CSRF same-origin checks on mutating non-webhook routes, rate limits enforced with Redis/Upstash (fail-open if Redis unavailable), feed fetch hardening (SSRF blocking, redirect revalidation, timeout + retries), conditional fetch support (ETag / Last-Modified), and reliable dedupe with DB-backed GUID/fingerprint uniqueness.

Docs follow-up (2026-02-11): import/export guidance is now beginner-friendly in product docs, including OPML folder-path flattening (/Tech/Web -> Tech / Web) and a clear improvement roadmap (preview import, selective export, duplicate conflict controls, portable JSON v3, scheduled backups).

Follow-up (2026-02-12): add-feed behavior for site URLs is now more reliable. Discovery fallback now probes www.<host> candidates when needed, and submit failures surface explicit error notices instead of silent no-op interactions.