diff --git a/.claude/skills/tina4-architect/SKILL.md b/.claude/skills/tina4-architect/SKILL.md
index 3763d0cc..b4263374 100644
--- a/.claude/skills/tina4-architect/SKILL.md
+++ b/.claude/skills/tina4-architect/SKILL.md
@@ -211,6 +211,7 @@ The happy path is the easy 20%. Walk this net for every journey and every featur
 - **Security** — secrets in `.env` not code; CORS closed by default; rate limits on public writes; form tokens on posts; no secrets in logs or URLs.
 - **Boundaries of scale** — never an unbounded list (paginate); eager-load to kill N+1; cache only where you measured a hit.
 - **The exit** — graceful shutdown drains in-flight work; migrations run on deploy; a backup exists.
+- **Mobile-first & responsive** — design the smallest screen first and enhance up with `min-width`; every journey must work on a phone, touch targets at least 44x44px. The `tina4-design` skill owns the detail.
 
 Nothing on this net is allowed to stay un-addressed by silence. That is the whole point of writing it down.
 
diff --git a/.claude/skills/tina4-developer-python/SKILL.md b/.claude/skills/tina4-developer-python/SKILL.md
index 495886a4..8833820c 100644
--- a/.claude/skills/tina4-developer-python/SKILL.md
+++ b/.claude/skills/tina4-developer-python/SKILL.md
@@ -1277,6 +1277,13 @@ against assumptions about another engine's compatibility.
   and subscript access (`{{ items[loop.index0 % 3] }}`) work as documented.
 - If a documented Frond feature misbehaves, that's a **framework bug** — report it (see below).
 
+### Mobile-first layout
+
+Build the smallest screen first, then enhance upward with `min-width` media queries - the base
+styles ARE the mobile styles, never a desktop layout patched down with `max-width`. Keep every
+interactive control at least 44x44px. Map tokens onto tina4-css; the `tina4-design` skill owns the
+full token + breakpoint detail. This is the default stance for any view you write.
+
 ### Web Push (Feature 140)
 
 Use `references/web-push.md` for the provider-neutral Web Push contract. Treat it as a standalone outbound integration, not WebSocket or Server-Sent Events. Keep it configuration-first, fail loudly on partial VAPID configuration, and install the optional `tina4-python[push]` capability only when the project enables it.
diff --git a/.claude/skills/tina4-js/SKILL.md b/.claude/skills/tina4-js/SKILL.md
index dad7b9ed..c9a408a1 100644
--- a/.claude/skills/tina4-js/SKILL.md
+++ b/.claude/skills/tina4-js/SKILL.md
@@ -729,6 +729,13 @@ batch(() => {
 });
 ```
 
+## Mobile-first layout
+
+Build the smallest screen first, then enhance upward with `min-width` media queries - the base
+styles ARE the mobile styles, never a desktop layout patched down with `max-width`. Keep every
+interactive control at least 44x44px. Map tokens onto tina4-css; the `tina4-design` skill owns the
+full token + breakpoint detail. This is the default stance for any component you build.
+
 ## HTML Templates — DOM Creation
 
 Read `references/html-and-components.md` for the full API. Quick reference: