diff --git a/src/App.jsx b/src/App.jsx
index 1235a89..eec455c 100644
--- a/src/App.jsx
+++ b/src/App.jsx
@@ -5,7 +5,47 @@ import { useAuth } from './auth/useAuth';
 import LoginPage from './components/LoginPage';
 import AppShell from './components/AppShell';
 import SectionPage from './pages/SectionPage';
-import { NAV_ITEMS } from './nav';
+import SubPage from './pages/SubPage';
+import { NAV_ITEMS, SUB_NAV } from './nav';
+
+function sectionRoutes(path) {
+  const subNav = SUB_NAV[path];
+  const routePath = path === '/' ? undefined : path.slice(1);
+
+  if (subNav) {
+    return (
+      <Route key={path} path={routePath} element={<SectionPage sectionPath={path} />}>
+        {subNav.map(({ segment, label }) =>
+          segment ? (
+            <Route
+              key={segment}
+              path={segment}
+              element={<SubPage title={label} />}
+            />
+          ) : (
+            <Route key="index" index element={<SubPage title={label} />} />
+          ),
+        )}
+      </Route>
+    );
+  }
+
+  const label = NAV_ITEMS.find((n) => n.path === path)?.label;
+
+  if (path === '/') {
+    return (
+      <Route key={path} index element={<SectionPage sectionPath={path}><SubPage title={label} /></SectionPage>} />
+    );
+  }
+
+  return (
+    <Route
+      key={path}
+      path={routePath}
+      element={<SectionPage sectionPath={path}><SubPage title={label} /></SectionPage>}
+    />
+  );
+}
 
 export default function App() {
   const { status } = useAuth();
@@ -34,17 +74,7 @@ export default function App() {
     <BrowserRouter>
       <Routes>
         <Route path="/" element={<AppShell />}>
-          {NAV_ITEMS.map(({ path, label }) =>
-            path === '/' ? (
-              <Route key={path} index element={<SectionPage title={label} />} />
-            ) : (
-              <Route
-                key={path}
-                path={path.slice(1)}
-                element={<SectionPage title={label} />}
-              />
-            ),
-          )}
+          {NAV_ITEMS.map((item) => sectionRoutes(item.path))}
           <Route path="*" element={<Navigate to="/" replace />} />
         </Route>
       </Routes>
diff --git a/src/components/AppShell.jsx b/src/components/AppShell.jsx
index efd9d0d..30e444b 100644
--- a/src/components/AppShell.jsx
+++ b/src/components/AppShell.jsx
@@ -7,7 +7,7 @@ import { NavLink, Outlet } from 'react-router-dom';
 import UserMenu from './UserMenu';
 import { NAV_ITEMS } from '../nav';
 
-const SIDEBAR_WIDTH = 240;
+const SIDEBAR_WIDTH = 144;
 
 export default function AppShell() {
   return (
@@ -31,8 +31,9 @@ export default function AppShell() {
               end={path === '/'}
               sx={(theme) => ({
                 borderRadius: 0,
-                px: 2,
+                px: 1.5,
                 py: 1.25,
+                borderLeft: '3px solid transparent',
                 color: theme.nav.item,
                 '& .MuiListItemIcon-root': { color: 'inherit' },
                 '&:hover': {
@@ -43,12 +44,11 @@ export default function AppShell() {
                   bgcolor: theme.nav.itemActive,
                   color: theme.nav.itemActiveText,
                   fontWeight: 600,
-                  borderLeft: `3px solid ${theme.nav.itemActiveAccent}`,
-                  pl: '13px',
+                  borderLeftColor: theme.nav.itemActiveAccent,
                 },
               })}
             >
-              <ListItemIcon sx={{ minWidth: 40 }}>
+              <ListItemIcon sx={{ minWidth: 36 }}>
                 <Icon />
               </ListItemIcon>
               <ListItemText primary={label} />
diff --git a/src/components/PageLayout.jsx b/src/components/PageLayout.jsx
index 2fd8f70..73a5d86 100644
--- a/src/components/PageLayout.jsx
+++ b/src/components/PageLayout.jsx
@@ -1,13 +1,68 @@
 import Box from '@mui/material/Box';
+import IconButton from '@mui/material/IconButton';
+import Tooltip from '@mui/material/Tooltip';
 import Typography from '@mui/material/Typography';
+import { NavLink } from 'react-router-dom';
+
+const SUB_NAV_WIDTH = 80;
+
+export default function PageLayout({ title, subNav, basePath, children }) {
+  const hasSubNav = subNav?.length > 0;
 
-export default function PageLayout({ title, children }) {
   return (
-    <Box>
-      <Typography variant="h5" sx={{ fontWeight: 700, mb: 2 }}>
-        {title}
-      </Typography>
-      {children}
+    <Box sx={{ display: 'flex', gap: 2, minHeight: 0 }}>
+      <Box
+        component={hasSubNav ? 'nav' : 'div'}
+        aria-label={hasSubNav ? 'Unternavigation' : undefined}
+        sx={{
+          width: SUB_NAV_WIDTH,
+          flexShrink: 0,
+          display: 'flex',
+          flexDirection: 'column',
+          alignItems: 'center',
+          gap: 1,
+        }}
+      >
+        {hasSubNav &&
+          subNav.map(({ segment, label, icon: Icon }) => {
+            const to = segment ? `${basePath}/${segment}` : basePath;
+
+            return (
+              <Tooltip key={segment || 'index'} title={label} placement="right">
+                <IconButton
+                  component={NavLink}
+                  to={to}
+                  end={!segment}
+                  aria-label={label}
+                  disableRipple
+                  sx={(theme) => ({
+                    width: 80,
+                    height: 80,
+                    color: theme.palette.text.secondary,
+                    bgcolor: 'transparent',
+                    '&:hover': {
+                      bgcolor: 'transparent',
+                      color: theme.palette.primary.main,
+                    },
+                    '&.active': {
+                      bgcolor: 'transparent',
+                      color: theme.palette.primary.main,
+                    },
+                  })}
+                >
+                  <Icon sx={{ fontSize: 40 }} />
+                </IconButton>
+              </Tooltip>
+            );
+          })}
+      </Box>
+
+      <Box sx={{ flexGrow: 1, minWidth: 0 }}>
+        <Typography variant="h5" sx={{ fontWeight: 700, mb: 2 }}>
+          {title}
+        </Typography>
+        {children}
+      </Box>
     </Box>
   );
 }
diff --git a/src/components/UserMenu.jsx b/src/components/UserMenu.jsx
index 80f4a48..c7e7480 100644
--- a/src/components/UserMenu.jsx
+++ b/src/components/UserMenu.jsx
@@ -17,7 +17,7 @@ export default function UserMenu() {
 
   return (
     <>
-      <Box sx={{ px: 2, py: 1.5, alignSelf: 'flex-start' }}>
+      <Box sx={{ px: 1.5, py: 1.5, alignSelf: 'flex-start' }}>
         <IconButton
           onClick={(e) => setAnchorEl(e.currentTarget)}
           sx={{ p: 0, width: 32, height: 32, borderRadius: '50%' }}
diff --git a/src/nav.js b/src/nav.js
index b5d8495..ac6a0fc 100644
--- a/src/nav.js
+++ b/src/nav.js
@@ -4,6 +4,13 @@ import LocalShippingIcon from '@mui/icons-material/LocalShipping';
 import AssignmentIcon from '@mui/icons-material/Assignment';
 import PeopleIcon from '@mui/icons-material/People';
 import InfoIcon from '@mui/icons-material/Info';
+import ViewListIcon from '@mui/icons-material/ViewList';
+import CategoryIcon from '@mui/icons-material/Category';
+import WarehouseIcon from '@mui/icons-material/Warehouse';
+import ListAltIcon from '@mui/icons-material/ListAlt';
+import ArchiveIcon from '@mui/icons-material/Archive';
+import GroupsIcon from '@mui/icons-material/Groups';
+import ContactPageIcon from '@mui/icons-material/ContactPage';
 
 export const NAV_ITEMS = [
   { path: '/', label: 'Home', icon: HomeIcon },
@@ -13,3 +20,20 @@ export const NAV_ITEMS = [
   { path: '/kunde', label: 'Kunde', icon: PeopleIcon },
   { path: '/infos', label: 'Infos', icon: InfoIcon },
 ];
+
+export const SUB_NAV = {
+  '/artikel': [
+    { segment: '', label: 'Übersicht', icon: ViewListIcon },
+    { segment: 'kategorien', label: 'Kategorien', icon: CategoryIcon },
+    { segment: 'lager', label: 'Lager', icon: WarehouseIcon },
+  ],
+  '/auftrag': [
+    { segment: '', label: 'Aktive Aufträge', icon: ListAltIcon },
+    { segment: 'archiv', label: 'Archiv', icon: ArchiveIcon },
+  ],
+  '/kunde': [
+    { segment: '', label: 'Kundenliste', icon: PeopleIcon },
+    { segment: 'gruppen', label: 'Gruppen', icon: GroupsIcon },
+    { segment: 'kontakte', label: 'Kontakte', icon: ContactPageIcon },
+  ],
+};
diff --git a/src/pages/SectionPage.jsx b/src/pages/SectionPage.jsx
index 448f217..35c6bcd 100644
--- a/src/pages/SectionPage.jsx
+++ b/src/pages/SectionPage.jsx
@@ -1,10 +1,20 @@
-import Typography from '@mui/material/Typography';
+import { Outlet, useLocation } from 'react-router-dom';
 import PageLayout from '../components/PageLayout';
+import { NAV_ITEMS, SUB_NAV } from '../nav';
+
+export default function SectionPage({ sectionPath, children }) {
+  const { pathname } = useLocation();
+  const title = NAV_ITEMS.find((item) => item.path === sectionPath)?.label ?? '';
+  const subNav = SUB_NAV[sectionPath];
+  const activeSub = subNav?.find((item) => {
+    const subPath = item.segment ? `${sectionPath}/${item.segment}` : sectionPath;
+    return pathname === subPath || pathname === `${subPath}/`;
+  });
+  const pageTitle = activeSub && subNav ? activeSub.label : title;
 
-export default function SectionPage({ title }) {
   return (
-    <PageLayout title={title}>
-      <Typography color="text.secondary">Inhalt folgt.</Typography>
+    <PageLayout title={pageTitle} subNav={subNav} basePath={sectionPath}>
+      {children ?? <Outlet />}
     </PageLayout>
   );
 }
diff --git a/src/pages/SubPage.jsx b/src/pages/SubPage.jsx
new file mode 100644
index 0000000..5f18e34
--- /dev/null
+++ b/src/pages/SubPage.jsx
@@ -0,0 +1,9 @@
+import Typography from '@mui/material/Typography';
+
+export default function SubPage({ title, description }) {
+  return (
+    <Typography color="text.secondary">
+      {description ?? `${title} — Inhalt folgt.`}
+    </Typography>
+  );
+}