diff --git a/cortex/routers/ui.py b/cortex/routers/ui.py
index 64599a3..3db4871 100644
--- a/cortex/routers/ui.py
+++ b/cortex/routers/ui.py
@@ -62,6 +62,20 @@ def _first_persona(username: str) -> str | None:
     return names[0] if names else None
 
 
+# ---------------------------------------------------------------------------
+# Favicon — default sparkle; persona pages override via JS
+# ---------------------------------------------------------------------------
+
+_FAVICON_SVG = (
+    "<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'>"
+    "<text y='.9em' font-size='90'>✨</text></svg>"
+)
+
+@router.get("/favicon.ico", include_in_schema=False)
+async def favicon():
+    return Response(content=_FAVICON_SVG, media_type="image/svg+xml")
+
+
 # ---------------------------------------------------------------------------
 # Root redirect
 # ---------------------------------------------------------------------------
diff --git a/cortex/static/app.js b/cortex/static/app.js
index db5b26e..3b700ec 100644
--- a/cortex/static/app.js
+++ b/cortex/static/app.js
@@ -32,6 +32,15 @@
 
         if (headerEmoji) headerEmoji.textContent = CORTEX_EMOJI;
 
+        // Set favicon to persona emoji
+        {
+            const favicon = document.querySelector("link[rel='icon']");
+            if (favicon && CORTEX_EMOJI) {
+                const svg = `<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 100 100'><text y='.9em' font-size='90'>${CORTEX_EMOJI}</text></svg>`;
+                favicon.href = `data:image/svg+xml,${encodeURIComponent(svg)}`;
+            }
+        }
+
         // Wire help link to preserve current persona on return
         const helpLink = document.getElementById('help-link');
         if (helpLink) helpLink.href = `/help?persona=${encodeURIComponent(CORTEX_PERSONA)}`;