diff --git a/CLAUDE.md b/CLAUDE.md
index 2cbba1f..149f778 100644
--- a/CLAUDE.md
+++ b/CLAUDE.md
@@ -15,9 +15,13 @@ plugins/
   okr/                   v1.0.0  — OKR guidance for Norwegian public sector
   ultraplan-local/       v3.3.0  — Brief, research, plan, execute, review, continue (six-command universal pipeline + multi-session resumption)
   ultra-cc-architect/    v0.1.0  — Claude-Code-specific architecture matching + skill-factory (extracted from ultraplan-local in v3.0.0)
+
+shared/
+  playground-design-system/  v0.1  — Aksel/Digdir-aligned CSS design system + JSON schemas for plugin Playgrounds (consumed by ms-ai-architect, okr, llm-security, ultraplan-local, config-audit)
+  playground-examples/             — Reference scenarios (ROS-Lier, OKR-Bærum, security-Vegvesen) + showcase landing
 ```
 
-Hvert plugin er selvstendig med egen CLAUDE.md, README, hooks, agents og commands.
+Hvert plugin er selvstendig med egen CLAUDE.md, README, hooks, agents og commands. `shared/` inneholder marketplace-nivå infrastruktur som flere plugins bygger på.
 
 ## Konvensjoner
 
diff --git a/README.md b/README.md
index bf147c6..6a2482d 100644
--- a/README.md
+++ b/README.md
@@ -239,6 +239,24 @@ Key commands: `/okr:skriv`, `/okr:kvalitet`, `/okr:gap`, `/okr:analyse`, `/okr:k
 
 ---
 
+## Shared infrastructure
+
+### [Playground Design System](shared/playground-design-system/) `v0.1`
+
+Shared design system for plugin Playgrounds — visual self-service UIs that complement terminal slash-commands. Aksel/Digdir-aligned aesthetics, WCAG 2.1 AA compliance, light + dark themes, A4 print stylesheets with B/W severity patterns.
+
+Targets five plugins: `ms-ai-architect`, `okr`, `llm-security`, `ultraplan-local`, `config-audit`. Built for Norwegian public sector decision-makers (kommunaldirektører, sikkerhetsoffiserer, OKR-koordinatorer) plus developer power-users — one visual family, two information densities.
+
+- **Tokens** — Inter font, body 17px, Digdir blue `#0062BA`, deuteranopia-safe severity ramp, distinct severity-red vs failure-red, plugin-scope colors, semantic CSS custom properties
+- **Tier 1 components** — radar/spider, 5×5 matrix-heatmap (bottom-left origin, ROS/DPIA), findings-browser, critique-card, wizard/stepper, live-meter with antipattern lints
+- **Tier 2 components** — decision-tree (AI Act 4-step), traffic-lights, diff-review, treemap (token hotspots), distribution P10/P50/P90, command-pipeline output, AI Act 4-color pyramide, pipeline-cockpit, verdict-pill + 5-band risk-meter, codepoint-reveal (Unicode steganography), small-multiples grid (16-category posture without overcrowded radar), OWASP badges (LLM/ASI/AST/MCP)
+- **JSON schemas** — `finding.schema.json`, `okr-set.schema.json`, `ros-threat.schema.json` for cross-plugin data interchange
+- **Reference scenarios** — Lier kommune ROS-rapport (ms-ai-architect), Bærum kommune T2 OKR live-writer, Statens vegvesen ToxicSkills findings review (85 funn, BLOCK)
+
+→ [Full documentation](shared/playground-design-system/README.md) · [Browse showcase](shared/playground-examples/index.html)
+
+---
+
 ## License
 
 MIT