diff --git a/dashboard/web/src/app/globals.css b/dashboard/web/src/app/globals.css
index 5705f97..ac6a154 100644
--- a/dashboard/web/src/app/globals.css
+++ b/dashboard/web/src/app/globals.css
@@ -5,6 +5,8 @@
 html,
 body {
   font-family: var(--ml-font-body), system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
+  background: var(--bl-bg-canvas);
+  color: var(--bl-text-primary);
 }
 
 @media (max-width: 767px) {
@@ -12,3 +14,97 @@ body {
     padding-top: 3.5rem;
   }
 }
+
+/*
+  Legacy pages still use Tailwind gray/white utilities directly. Keep them
+  theme-aware while those pages are migrated to shared @bytelyst/ui primitives.
+*/
+[data-theme="dark"] .bg-white {
+  background-color: var(--bl-surface-card) !important;
+}
+
+[data-theme="dark"] .bg-gray-50,
+[data-theme="dark"] .bg-gray-100 {
+  background-color: var(--bl-bg-canvas) !important;
+}
+
+[data-theme="dark"] .bg-gray-200,
+[data-theme="dark"] .bg-gray-300 {
+  background-color: var(--bl-surface-muted) !important;
+}
+
+[data-theme="dark"] .bg-gray-700,
+[data-theme="dark"] .bg-gray-800 {
+  background-color: var(--bl-surface-card) !important;
+}
+
+[data-theme="dark"] .bg-blue-50,
+[data-theme="dark"] .bg-green-50,
+[data-theme="dark"] .bg-yellow-50,
+[data-theme="dark"] .bg-red-50,
+[data-theme="dark"] .bg-purple-50,
+[data-theme="dark"] .bg-red-50\/40 {
+  background-color: var(--bl-surface-muted) !important;
+}
+
+[data-theme="dark"] .text-gray-900,
+[data-theme="dark"] .text-gray-800,
+[data-theme="dark"] .text-gray-700 {
+  color: var(--bl-text-primary) !important;
+}
+
+[data-theme="dark"] .text-gray-600,
+[data-theme="dark"] .text-gray-500,
+[data-theme="dark"] .text-gray-400,
+[data-theme="dark"] .text-gray-300 {
+  color: var(--bl-text-secondary) !important;
+}
+
+[data-theme="dark"] .border-gray-100,
+[data-theme="dark"] .border-gray-200,
+[data-theme="dark"] .border-gray-300,
+[data-theme="dark"] .border-gray-600 {
+  border-color: var(--bl-border) !important;
+}
+
+[data-theme="dark"] .border-blue-200,
+[data-theme="dark"] .border-green-200,
+[data-theme="dark"] .border-yellow-200,
+[data-theme="dark"] .border-red-200,
+[data-theme="dark"] .border-purple-200 {
+  border-color: var(--bl-border) !important;
+}
+
+[data-theme="dark"] input,
+[data-theme="dark"] select,
+[data-theme="dark"] textarea {
+  background-color: var(--bl-input) !important;
+  border-color: var(--bl-border) !important;
+  color: var(--bl-text-primary) !important;
+}
+
+[data-theme="dark"] input::placeholder,
+[data-theme="dark"] textarea::placeholder {
+  color: var(--bl-text-tertiary) !important;
+}
+
+[data-theme="dark"] .shadow,
+[data-theme="dark"] .shadow-md,
+[data-theme="dark"] .shadow-lg,
+[data-theme="dark"] .shadow-xl,
+[data-theme="dark"] .shadow-sm {
+  box-shadow: var(--bl-shadow-sm) !important;
+}
+
+@media (hover: hover) {
+  [data-theme="dark"] .hover\:bg-gray-50:hover,
+  [data-theme="dark"] .hover\:bg-gray-100:hover,
+  [data-theme="dark"] .hover\:bg-gray-200:hover {
+    background-color: var(--bl-surface-muted) !important;
+  }
+
+  [data-theme="dark"] .hover\:text-gray-600:hover,
+  [data-theme="dark"] .hover\:text-gray-700:hover {
+    color: var(--bl-text-primary) !important;
+  }
+}
diff --git a/dashboard/web/src/components/sidebar-nav.tsx b/dashboard/web/src/components/sidebar-nav.tsx
index 3a82183..332311c 100644
--- a/dashboard/web/src/components/sidebar-nav.tsx
+++ b/dashboard/web/src/components/sidebar-nav.tsx
@@ -23,6 +23,7 @@ import { useAuth } from '@/lib/auth';
 
 const THEME_STORAGE_KEY = 'bytelyst.theme.v1';
 const SIDEBAR_STORAGE_KEY = 'bytelyst.devops.sidebar.collapsed.v1';
+const THEME_EVENT = 'bytelyst-theme-change';
 type Theme = 'light' | 'dark';
 
 const navItems = [
@@ -46,6 +47,14 @@ export function SidebarNav() {
   const [theme, setTheme] = useState<Theme>('dark');
 
   useEffect(() => {
+    function handleThemeChange(event: Event) {
+      const next = (event as CustomEvent<Theme>).detail;
+      if (next === 'light' || next === 'dark') {
+        setTheme(next);
+        applyTheme(next);
+      }
+    }
+
     try {
       const savedTheme = window.localStorage.getItem(THEME_STORAGE_KEY) as Theme | null;
       const legacyTheme = window.localStorage.getItem('theme') as Theme | null;
@@ -61,6 +70,9 @@ export function SidebarNav() {
     } catch {
       applyTheme('dark');
     }
+
+    window.addEventListener(THEME_EVENT, handleThemeChange);
+    return () => window.removeEventListener(THEME_EVENT, handleThemeChange);
   }, []);
 
   function applyTheme(next: Theme) {
@@ -75,6 +87,7 @@ export function SidebarNav() {
     try {
       window.localStorage.setItem(THEME_STORAGE_KEY, next);
       window.localStorage.setItem('theme', next);
+      window.dispatchEvent(new CustomEvent(THEME_EVENT, { detail: next }));
     } catch {
       // localStorage can be unavailable in private browsing.
     }
diff --git a/dashboard/web/src/components/theme-toggle.tsx b/dashboard/web/src/components/theme-toggle.tsx
index 0a63b21..2ccaa17 100644
--- a/dashboard/web/src/components/theme-toggle.tsx
+++ b/dashboard/web/src/components/theme-toggle.tsx
@@ -13,6 +13,7 @@ import { Button } from '@/components/ui/Primitives';
 // `app/layout.tsx`.
 
 const STORAGE_KEY = 'bytelyst.theme.v1';
+const THEME_EVENT = 'bytelyst-theme-change';
 type Theme = 'dark' | 'light';
 const THEMES: Theme[] = ['dark', 'light'];
 
@@ -30,6 +31,7 @@ function readPersisted(): Theme {
 function applyTheme(theme: Theme) {
   if (typeof document === 'undefined') return;
   document.documentElement.setAttribute('data-theme', theme);
+  document.documentElement.classList.toggle('dark', theme === 'dark');
 }
 
 export function ThemeToggle() {
@@ -37,14 +39,31 @@ export function ThemeToggle() {
   const [theme, setTheme] = useState<Theme>('dark');
 
   useEffect(() => {
-    setTheme(readPersisted());
+    const persisted = readPersisted();
+    setTheme(persisted);
+    applyTheme(persisted);
+
+    function handleThemeChange(event: Event) {
+      const next = (event as CustomEvent<Theme>).detail;
+      if ((THEMES as string[]).includes(next)) {
+        setTheme(next);
+        applyTheme(next);
+      }
+    }
+
+    window.addEventListener(THEME_EVENT, handleThemeChange);
+    return () => window.removeEventListener(THEME_EVENT, handleThemeChange);
   }, []);
 
   const toggle = useCallback(() => {
     setTheme((prev) => {
       const next = prev === 'dark' ? 'light' : 'dark';
       try {
-        if (typeof window !== 'undefined') window.localStorage.setItem(STORAGE_KEY, next);
+        if (typeof window !== 'undefined') {
+          window.localStorage.setItem(STORAGE_KEY, next);
+          window.localStorage.setItem('theme', next);
+          window.dispatchEvent(new CustomEvent(THEME_EVENT, { detail: next }));
+        }
       } catch {
         // ignore
       }