Index: app/(app)/layout.tsx
===================================================================
--- app/(app)/layout.tsx	(revision 32d8e905d10b831e0f58a954b005d98221c72595)
+++ app/(app)/layout.tsx	(revision e6c9f4b6451f09b5876b51914dfde694dd2ed191)
@@ -1,4 +1,5 @@
 import { auth } from '@/auth';
 import { redirect } from 'next/navigation';
+import BottomNav from '@/app/ui/bottom-nav';
 
 export default async function AppLayout({
@@ -14,8 +15,12 @@
 
     return (
-        <div className="flex-1 flex flex-col">
-            {children}
+        <div className="flex-1 flex flex-col h-full">
+            <main className="flex-1 flex flex-col pb-24">
+                {children}
+            </main>
+
+            {/* Fixed bottom navigation */}
+            <BottomNav />
         </div>
-        /* bottom nav goes here later */
     );
 }
Index: app/ui/bottom-nav.tsx
===================================================================
--- app/ui/bottom-nav.tsx	(revision e6c9f4b6451f09b5876b51914dfde694dd2ed191)
+++ app/ui/bottom-nav.tsx	(revision e6c9f4b6451f09b5876b51914dfde694dd2ed191)
@@ -0,0 +1,109 @@
+'use client';
+
+import Link from 'next/link';
+import { usePathname } from 'next/navigation';
+import {
+    HomeIcon,
+    ClockIcon,
+    ChartBarIcon,
+    UserIcon,
+    PlusIcon,
+} from '@heroicons/react/24/outline';
+
+const TABS = [
+    { href: '/home', icon: HomeIcon },
+    { href: '/history', icon: ClockIcon },
+    { href: '/analytics', icon: ChartBarIcon },
+    { href: '/profile', icon: UserIcon },
+];
+
+export default function BottomNav() {
+    const pathname = usePathname();
+
+    const isAddPage = pathname.startsWith('/add');
+
+    return (
+        <div className="relative">
+            {/* Floating bar */}
+            <nav
+                className="
+                    pointer-events-auto
+                    pb-safe
+                    mx-4
+                    mb-4
+                    h-14
+                    rounded-2xl
+                    bg-black/40
+                    backdrop-blur-md
+                    shadow-lg
+                    border
+                    border-white/10
+                    flex
+                    items-center
+                    justify-center
+                    px-6
+                    gap-11
+                "
+            >
+                {/* Left tabs */}
+                <div className="flex gap-11">
+                    {TABS.slice(0, 2).map(({ href, icon: Icon }) => {
+                        const active = pathname.startsWith(href);
+                        return (
+                            <Link key={href} href={href}>
+                                <Icon
+                                    className={`h-6 w-6 ${active ? 'text-blue-500' : 'text-white/60'
+                                        }`}
+                                />
+                            </Link>
+                        );
+                    })}
+                </div>
+
+                {/* Spacer for center button */}
+                <div className="w-12" />
+
+                {/* Right tabs */}
+                <div className="flex gap-11">
+                    {TABS.slice(2).map(({ href, icon: Icon }) => {
+                        const active = pathname.startsWith(href);
+                        return (
+                            <Link key={href} href={href}>
+                                <Icon
+                                    className={`h-6 w-6 ${active ? 'text-blue-500' : 'text-white/60'
+                                        }`}
+                                />
+                            </Link>
+                        );
+                    })}
+                </div>
+            </nav>
+
+            {/* Center plus button */}
+            <Link
+                href="/add"
+                className="
+                    absolute
+                    left-1/2
+                    -top-6
+                    -translate-x-1/2
+                    h-14
+                    w-14
+                    rounded-full
+                    flex
+                    items-center
+                    justify-center
+                    shadow-xl
+                    border
+                    border-white/20
+                    backdrop-blur-md
+                "
+                style={{
+                    backgroundColor: isAddPage ? '#9CA3AF' : '#3B82F6',
+                }}
+            >
+                <PlusIcon className="h-7 w-7 text-white" />
+            </Link>
+        </div>
+    );
+}
Index: app/ui/global.css
===================================================================
--- app/ui/global.css	(revision 32d8e905d10b831e0f58a954b005d98221c72595)
+++ app/ui/global.css	(revision e6c9f4b6451f09b5876b51914dfde694dd2ed191)
@@ -27,2 +27,6 @@
   }
 }
+
+.pb-safe {
+  padding-bottom: env(safe-area-inset-bottom);
+}