Update styling across app

docs/DESIGN_SYSTEM.md

@@ -45,6 +45,22 @@ Use the spacing tokens for new components. Prefer `8px`, `12px`, and `20px` gaps
 - Maximum content width: approximately 1400–1640px.
 - Larger headings and more generous vertical rhythm are appropriate.
 - Preserve the grid background and orange accents.
+- Catalogue and editorial pages use `catalogue-hero` for an angular introductory
+  panel and may pair it with a compact operational control bar.
+- Community build cards retain the colored top rule, abstract loadout artwork,
+  concise tags, agent attribution, and a full-width terminal action.
+
+### Agent and authentication surfaces
+
+- Account pages should read as an agent dossier: identity and access at the top,
+  activity metrics beside it, archives in the primary column, and security
+  controls in a narrower console column.
+- Authentication pages use a split frame: contextual SHD network information on
+  the left and the actionable secure-access console on the right.
+- OAuth providers appear as connection nodes with a recognizable provider color;
+  SHD orange remains reserved for the primary local action and navigation.
+- On small screens, the split frame becomes a single column and account controls
+  move before archival content.
 
 ### Admin dashboard
 
@@ -98,3 +114,17 @@ Do not communicate state by color alone; include a label, icon, or pattern.
 6. Verify keyboard focus, pending behavior, empty states, mobile layout, and archived data behavior.
 
 If a new interface needs a genuinely new pattern, document it here when introducing it.
+
+## Design-system governance
+
+Significant visual and interaction changes must update this document and the
+shared implementation in the same change. A change is significant when it
+introduces or materially revises a reusable token, component pattern, layout,
+responsive rule, accessibility behavior, motion behavior, or state convention.
+
+Small alignment corrections and isolated visual bug fixes do not require a
+documentation change unless they establish a rule that other interfaces should
+follow.
+
+Repository agents and contributors should follow the maintenance checklist in
+`AGENTS.md`.