design overhaul + expenses page

- Stripe-style theme: single indigo (#635BFF) brand, 6px radius,
  Inter scale; rewritten themePrimitives + MUI customizations
  (solid primary, near-black secondary, severity-aware Alert)
- Sticky Header (brand-left nav, theme toggle, mobile drawer),
  inline Footer, route fade-in, per-route document.title
- Home hero + feature cards (dead /dashboard,/reports links replaced)
- Split-panel AuthPage with validation and password visibility
- Data pages: PageHeader/EmptyState, breadcrumbed Fetch Request
  pages, admin table polish (numeric alignment, row-hover actions,
  skeletons, empty states), single-accent admin SideMenu
- Global ToastProvider wired into app shell
- New /expenses page: month-grouped feed, single-open accordion
  with inline detail (account, tags, amount, timestamps)

react-openapi/src/components/ResourceDetail.tsx

@@ -58,9 +58,14 @@ export function ResourceDetail({ resource, basePath }: ResourceDetailProps) {
 
   if (!data) {
     return (
-      <Typography variant="body1" color="text.secondary" sx={{ py: 4 }}>
-        Record not found
-      </Typography>
+      <Box sx={{ py: 6, textAlign: "center" }}>
+        <Typography variant="body2" color="text.secondary">
+          Record not found
+        </Typography>
+        <Button sx={{ mt: 1.5 }} onClick={() => navigate(`${basePath}/${resource.name}`)}>
+          Back to list
+        </Button>
+      </Box>
     );
   }
 
@@ -82,7 +87,7 @@ export function ResourceDetail({ resource, basePath }: ResourceDetailProps) {
         <Button startIcon={<ArrowBackIcon />} onClick={() => navigate(`${basePath}/${resource.name}`)}>
           Back
         </Button>
-        <Typography variant="h5" fontWeight={700} sx={{ flex: 1 }}>
+        <Typography variant="h5" fontWeight={700} sx={{ flex: 1, letterSpacing: "-0.02em" }}>
           {applyDisplayFormat(
             Object.fromEntries(
               resource.orderedFields.map((field) => {