Fix: Localized Dates

src/components/layouts/MfaEnforcementLayout.tsx

@@ -7,6 +7,7 @@ import { useAuth } from '@/contexts/AuthContext';
 import { AddPasskeyWizard } from '@/components/security/AddPasskeyWizard';
 import { TotpEnrollmentWizard } from '@/components/security/TotpEnrollmentWizard';
 import { api } from '@/lib/api';
+import { formatDate } from '@/lib/date';
 
 export default function MfaEnforcementLayout() {
   const navigate = useNavigate();
@@ -124,7 +125,7 @@ export default function MfaEnforcementLayout() {
             {mfaCompliance?.deadline_at && (
               <div className="p-3 rounded-lg bg-destructive/10 border border-destructive/20 text-center">
                 <p className="text-sm font-medium text-destructive">
-                  Deadline: {new Date(mfaCompliance.deadline_at).toLocaleDateString()}
+                  Deadline: {formatDate(mfaCompliance.deadline_at)}
                 </p>
               </div>
             )}

src/lib/date.ts

@@ -0,0 +1,108 @@
+/**
+ * Date/time formatting utilities.
+ *
+ * All timestamps from the API are stored in UTC (ISO 8601, e.g.
+ * "2026-03-06T14:30:00Z" or "2026-03-06T14:30:00.000Z").  This module
+ * provides helpers that always parse those strings as UTC and then render
+ * them in the *user's local timezone* as reported by the browser.
+ *
+ * Usage
+ * -----
+ *   import { formatDateTime, formatDate, formatRelative } from "@/lib/date";
+ *
+ *   formatDateTime("2026-03-06T14:30:00Z")
+ *   // → "Mar 6, 2026, 2:30:00 PM"  (user's local tz)
+ *
+ *   formatDate("2026-03-06T14:30:00Z")
+ *   // → "Mar 6, 2026"
+ *
+ *   formatRelative("2026-03-06T14:30:00Z")
+ *   // → "5 minutes ago"  (via Intl.RelativeTimeFormat)
+ */
+
+/**
+ * Ensure the raw API string is treated as UTC.
+ * The backend BaseModel serialises with a trailing "Z", but we handle
+ * the "+00:00" form and bare ISO strings (YYYY-MM-DDTHH:MM:SS) too.
+ */
+function toUtcDate(raw: string | null | undefined): Date | null {
+  if (!raw) return null;
+  // Already ends with Z or has an offset → parse directly
+  if (raw.endsWith("Z") || /[+-]\d{2}:\d{2}$/.test(raw)) {
+    return new Date(raw);
+  }
+  // Bare ISO string without timezone → treat as UTC
+  return new Date(raw + "Z");
+}
+
+/**
+ * Format a UTC timestamp as a human-readable date + time in the user's
+ * local timezone.
+ *
+ * @param raw  - ISO 8601 UTC string from the API
+ * @param opts - Optional Intl.DateTimeFormatOptions overrides
+ */
+export function formatDateTime(
+  raw: string | null | undefined,
+  opts?: Intl.DateTimeFormatOptions
+): string {
+  const d = toUtcDate(raw);
+  if (!d || isNaN(d.getTime())) return "—";
+  return new Intl.DateTimeFormat(undefined, {
+    year: "numeric",
+    month: "short",
+    day: "numeric",
+    hour: "numeric",
+    minute: "2-digit",
+    second: "2-digit",
+    hour12: false,
+    ...opts,
+  }).format(d);
+}
+
+/**
+ * Format a UTC timestamp as a date-only string in the user's local timezone.
+ */
+export function formatDate(
+  raw: string | null | undefined,
+  opts?: Intl.DateTimeFormatOptions
+): string {
+  const d = toUtcDate(raw);
+  if (!d || isNaN(d.getTime())) return "—";
+  return new Intl.DateTimeFormat(undefined, {
+    year: "numeric",
+    month: "short",
+    day: "numeric",
+    ...opts,
+  }).format(d);
+}
+
+/**
+ * Format a UTC timestamp as a concise time-ago string.
+ * Falls back to formatDateTime for dates older than 30 days.
+ */
+export function formatRelative(raw: string | null | undefined): string {
+  const d = toUtcDate(raw);
+  if (!d || isNaN(d.getTime())) return "—";
+
+  const diffMs = d.getTime() - Date.now();
+  const diffSec = Math.round(diffMs / 1000);
+  const absSec = Math.abs(diffSec);
+
+  const rtf = new Intl.RelativeTimeFormat(undefined, { numeric: "auto" });
+
+  if (absSec < 60) return rtf.format(diffSec, "second");
+  if (absSec < 3600) return rtf.format(Math.round(diffSec / 60), "minute");
+  if (absSec < 86400) return rtf.format(Math.round(diffSec / 3600), "hour");
+  if (absSec < 86400 * 30) return rtf.format(Math.round(diffSec / 86400), "day");
+
+  return formatDateTime(raw);
+}
+
+/**
+ * Return a Date object for a UTC ISO string (or null on invalid input).
+ * Useful when you need to compare timestamps.
+ */
+export function parseUtcDate(raw: string | null | undefined): Date | null {
+  return toUtcDate(raw);
+}

src/pages/admin/AdminUsersPage.tsx

@@ -61,7 +61,8 @@ import { useAuth } from "@/contexts/AuthContext";
 
 function formatDate(d: string | null) {
   if (!d) return "—";
-  return new Date(d).toLocaleDateString(undefined, { year: "numeric", month: "short", day: "numeric" });
+  const raw = !(d.endsWith("Z") || /[+-]\d{2}:\d{2}$/.test(d)) ? d + "Z" : d;
+  return new Intl.DateTimeFormat(undefined, { year: "numeric", month: "short", day: "numeric" }).format(new Date(raw));
 }
 
 function capitalize(s: string) {

src/pages/org/CompliancePage.tsx

@@ -10,6 +10,7 @@ import { api, OrgComplianceMember, create403Handler } from "@/lib/api";
 import { useQuery, useMutation } from "@tanstack/react-query";
 import { useToast } from "@/hooks/use-toast";
 import { useOrg } from "@/contexts/OrgContext";
+import { formatDate } from "@/lib/date";
 
 const STATUS_CONFIG: Record<string, { label: string; color: string; icon: typeof Clock }> = {
   compliant: {
@@ -231,7 +232,7 @@ export default function CompliancePage() {
                       {member.deadline_at && member.status !== 'compliant' && member.status !== 'not_applicable' && (
                         <div className="text-sm text-muted-foreground">
                           <span className="hidden md:inline">Deadline: </span>
-                          {new Date(member.deadline_at).toLocaleDateString()}
+                          {formatDate(member.deadline_at)}
                         </div>
                       )}
                       

src/pages/org/MembersPage.tsx

@@ -84,11 +84,8 @@ const getInitials = (name: string | null | undefined): string => {
 
 function formatDate(d: string | null | undefined) {
   if (!d) return "—";
-  return new Date(d).toLocaleDateString(undefined, {
-    year: "numeric",
-    month: "short",
-    day: "numeric",
-  });
+  const raw = typeof d === "string" && !(d.endsWith("Z") || /[+-]\d{2}:\d{2}$/.test(d)) ? d + "Z" : d;
+  return new Intl.DateTimeFormat(undefined, { year: "numeric", month: "short", day: "numeric" }).format(new Date(raw));
 }
 
 function capitalize(s: string) {

src/pages/user/ActivityPage.tsx

@@ -7,6 +7,7 @@ import { Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from "@
 import { Tabs, TabsList, TabsTrigger } from "@/components/ui/tabs";
 import { api, AuditLogEntry } from "@/lib/api";
 import { useAuth } from "@/contexts/AuthContext";
+import { formatDateTime } from "@/lib/date";
 
 // Map audit log action strings to display info
 const getEventDisplay = (action: string) => {
@@ -56,15 +57,7 @@ export default function ActivityPage() {
 
   useEffect(() => { loadEvents(); }, [view]); // eslint-disable-line react-hooks/exhaustive-deps
 
-  const formatDate = (dateString: string) => {
-    const date = new Date(dateString);
-    return new Intl.DateTimeFormat("en-US", {
-      month: "short",
-      day: "numeric",
-      hour: "numeric",
-      minute: "2-digit",
-    }).format(date);
-  };
+  const formatDate = (dateString: string) => formatDateTime(dateString, { month: "short", day: "numeric", hour: "numeric", minute: "2-digit" });
 
   const filteredEvents = events.filter((e) => {
     if (filter === "all") return true;

src/pages/user/SSHKeysPage.tsx

@@ -48,6 +48,7 @@ import {
 } from "@/components/ui/alert-dialog";
 import { useToast } from "@/hooks/use-toast";
 import { api, SSHKey, SSHCertificate, ApiError, PrincipalOption, MyPrincipalsOrg, DeptCertPolicy } from "@/lib/api";
+import { formatDate as _formatDate } from "@/lib/date";
 
 // ──────────────────────────────────────────────────────────────────────────────
 // Helpers
@@ -55,11 +56,7 @@ import { api, SSHKey, SSHCertificate, ApiError, PrincipalOption, MyPrincipalsOrg
 
 function formatDate(dateStr: string | null): string {
   if (!dateStr) return "—";
-  return new Date(dateStr).toLocaleDateString(undefined, {
-    year: "numeric",
-    month: "short",
-    day: "numeric",
-  });
+  return _formatDate(dateStr);
 }
 
 function CopyButton({ text }: { text: string }) {

src/pages/user/SecurityPage.tsx

@@ -246,13 +246,13 @@ export default function SecurityPage() {
 
   const formatLastUsed = (date: string | null) => {
     if (!date) return "Never";
-    const d = new Date(date);
+    const d = new Date(date.endsWith("Z") || /[+-]\d{2}:\d{2}$/.test(date) ? date : date + "Z");
     const now = new Date();
     const diffDays = Math.floor((now.getTime() - d.getTime()) / (1000 * 60 * 60 * 24));
     if (diffDays === 0) return "Today";
     if (diffDays === 1) return "Yesterday";
     if (diffDays < 7) return `${diffDays} days ago`;
-    return d.toLocaleDateString();
+    return new Intl.DateTimeFormat(undefined, { year: "numeric", month: "short", day: "numeric" }).format(d);
   };
 
   return (