diff --git a/AGENTS.md b/AGENTS.md
index 1a255fc0..67df8071 100644
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -69,6 +69,7 @@ Document the run in PR descriptions so QA can cross-reference results.
 * **Nostr interoperability:** Keep kind `30078` events as the source of truth and optionally mirror to kind `1063` so external clients see the hosted URL.
 * **Probing:** Lightweight `HEAD`/`GET` requests should back `probeUrl()` so dead URLs can be hidden or flagged without blocking the UI.
 * **Extensibility:** Future work (live streams, NIP-96 uploads, analytics) should preserve the URL-first strategy and magnet safety rules above.
+* **Sidebar layering:** Keep the fixed sidebar below every modal and overlay. Respect the `--z-sidebar*` tokens so dialogs always render on top of the navigation.
 
 ---
 
diff --git a/css/style.css b/css/style.css
index 5701604e..17310431 100644
--- a/css/style.css
+++ b/css/style.css
@@ -14,8 +14,9 @@
   --scrollbar-track: rgba(255, 255, 255, 0.1);
   --scrollbar-thumb: rgba(255, 255, 255, 0.3);
   --scrollbar-thumb-hover: rgba(255, 255, 255, 0.4);
-  --z-sidebar: 40;
-  --z-sidebar-overlay: 30;
+  /* Sidebar stack must remain below modal overlays. */
+  --z-sidebar: 30;
+  --z-sidebar-overlay: 20;
   --z-modal-root: 80;
   --z-modal-overlay: 70;
   --z-modal-content: 90;