diff --git a/frontend/src/components/AuthGate.tsx b/frontend/src/components/AuthGate.tsx
index d9569387..632fd3cf 100644
--- a/frontend/src/components/AuthGate.tsx
+++ b/frontend/src/components/AuthGate.tsx
@@ -1,10 +1,12 @@
 import { useEffect, useState, createContext, useContext } from 'react'
 import type { User } from '../types'
 
-const SHARED_TIMEOUT_MS = 10 * 60 * 1000
-
-function isSharedDevice() {
-  return document.cookie.split(';').some(c => c.trim() === 'hnf_shared_device=1')
+function getInactivityMs(): number | null {
+  if (window.matchMedia('(display-mode: standalone)').matches) return null
+  const c = document.cookie.split(';').map(s => s.trim()).find(s => s.startsWith('hnf_inactivity_mins='))
+  if (!c) return null
+  const mins = parseInt(c.split('=')[1])
+  return isNaN(mins) || mins <= 0 ? null : mins * 60 * 1000
 }
 
 
diff --git a/frontend/src/index.css b/frontend/src/index.css
index a7824e2b..d33b9c67 100644
--- a/frontend/src/index.css
+++ b/frontend/src/index.css
@@ -395,3 +395,18 @@ html, body, #root {
   .report-view { padding: 16px; }
   .report-controls { gap: 8px; }
 }
+
+/* Sidebar scrollbar */
+.nav-scroll::-webkit-scrollbar,
+.sidebar::-webkit-scrollbar,
+.sidebar-nav::-webkit-scrollbar { width: 4px; }
+.nav-scroll::-webkit-scrollbar-track,
+.sidebar::-webkit-scrollbar-track,
+.sidebar-nav::-webkit-scrollbar-track { background: transparent; }
+.nav-scroll::-webkit-scrollbar-thumb,
+.sidebar::-webkit-scrollbar-thumb,
+.sidebar-nav::-webkit-scrollbar-thumb { background: rgba(201,168,76,0.35); border-radius: 2px; }
+.nav-scroll::-webkit-scrollbar-thumb:hover,
+.sidebar::-webkit-scrollbar-thumb:hover,
+.sidebar-nav::-webkit-scrollbar-thumb:hover { background: rgba(201,168,76,0.65); }
+.nav-scroll, .sidebar, .sidebar-nav { scrollbar-width: thin; scrollbar-color: rgba(201,168,76,0.35) transparent; }