diff --git a/frontend/app/(seeker)/_layout.tsx b/frontend/app/(seeker)/_layout.tsx
index 8a7a921..08b479c 100644
--- a/frontend/app/(seeker)/_layout.tsx
+++ b/frontend/app/(seeker)/_layout.tsx
@@ -5,11 +5,20 @@
 import { Tabs } from "expo-router";
 import { Text } from "react-native";
 
+import {
+  NAV_HEADER_STYLE,
+  NAV_HEADER_TINT_COLOR,
+  NAV_HEADER_TITLE_STYLE,
+} from "@/lib/theme";
+
 export default function SeekerLayout() {
   return (
     <Tabs
       screenOptions={{
         headerShown: true,
+        headerStyle: NAV_HEADER_STYLE,
+        headerTintColor: NAV_HEADER_TINT_COLOR,
+        headerTitleStyle: NAV_HEADER_TITLE_STYLE,
         tabBarStyle: { minHeight: 64, paddingBottom: 8, paddingTop: 8 },
         tabBarLabelStyle: { fontSize: 14, fontWeight: "600" },
         tabBarActiveTintColor: "#2563EB",
diff --git a/frontend/app/(volunteer)/_layout.tsx b/frontend/app/(volunteer)/_layout.tsx
index b310963..79aeb41 100644
--- a/frontend/app/(volunteer)/_layout.tsx
+++ b/frontend/app/(volunteer)/_layout.tsx
@@ -5,11 +5,20 @@
 import { Tabs } from "expo-router";
 import { Text } from "react-native";
 
+import {
+  NAV_HEADER_STYLE,
+  NAV_HEADER_TINT_COLOR,
+  NAV_HEADER_TITLE_STYLE,
+} from "@/lib/theme";
+
 export default function VolunteerLayout() {
   return (
     <Tabs
       screenOptions={{
         headerShown: true,
+        headerStyle: NAV_HEADER_STYLE,
+        headerTintColor: NAV_HEADER_TINT_COLOR,
+        headerTitleStyle: NAV_HEADER_TITLE_STYLE,
         tabBarStyle: { minHeight: 64, paddingBottom: 8, paddingTop: 8 },
         tabBarLabelStyle: { fontSize: 14, fontWeight: "600" },
         tabBarActiveTintColor: "#2563EB",
diff --git a/frontend/lib/theme.ts b/frontend/lib/theme.ts
new file mode 100644
index 0000000..7c85073
--- /dev/null
+++ b/frontend/lib/theme.ts
@@ -0,0 +1,14 @@
+/**
+ * Shared theme constants for navigation and UI styling.
+ */
+
+export const NAV_HEADER_STYLE = {
+  backgroundColor: "#2563EB",
+} as const;
+
+export const NAV_HEADER_TINT_COLOR = "#FFFFFF";
+
+export const NAV_HEADER_TITLE_STYLE = {
+  fontWeight: "700" as const,
+  fontSize: 18,
+};