diff --git a/src/Navigation.tsx b/src/Navigation.tsx
index 70ddd3bc00..354a5baf15 100644
--- a/src/Navigation.tsx
+++ b/src/Navigation.tsx
@@ -30,6 +30,7 @@ import {logger as notyLogger} from '#/lib/notifications/util'
 import {buildStateObject} from '#/lib/routes/helpers'
 import {
   type AllNavigatorParams,
+  type AuthNavigatorParams,
   type BottomTabNavigatorParams,
   type CoreNavigatorParams,
   type FlatNavigatorParams,
@@ -149,10 +150,12 @@ import {useNonReactiveCallback} from './lib/hooks/useNonReactiveCallback'
 import {useLoggedOutViewControls} from './state/shell/logged-out'
 import {useLoggedOutView} from './state/shell/logged-out'
 import {useCloseAllActiveElements} from './state/util'
+import {AuthModal} from './view/shell/desktop/AuthLayout'
 
 const navigationRef = createNavigationContainerRef<AllNavigatorParams>()
 
 const Core = createNativeStackNavigator<CoreNavigatorParams>()
+const Auth = createNativeStackNavigator<AuthNavigatorParams>()
 const HomeTab = createNativeStackNavigatorWithAuth<HomeTabNavigatorParams>()
 const SearchTab = createNativeStackNavigatorWithAuth<SearchTabNavigatorParams>()
 const NotificationsTab =
@@ -778,10 +781,74 @@ const FlatNavigator = () => {
         options={{title: title(msg`Home`)}}
       />
       {commonScreens(Flat, numUnread)}
+      <Flat.Screen
+        name="Auth"
+        getComponent={() => AuthNavigator}
+        options={{
+          title: title(msg`Login or Sign Up`),
+          presentation: 'modal',
+        }}
+      />
     </Flat.Navigator>
   )
 }
 
+function AuthNavigator() {
+  const t = useTheme()
+  return (
+    <Auth.Navigator screenOptions={screenOptions(t)} layout={AuthModal}>
+      {authScreens({navigator: Auth})}
+    </Auth.Navigator>
+  )
+}
+
+function authScreens({navigator: Navigator}: {navigator: typeof Auth}) {
+  return (
+    <>
+      <Navigator.Screen
+        name="Landing"
+        getComponent={() => LandingScreen}
+        options={{animation: 'fade', animationDuration: 200}}
+      />
+      <Navigator.Screen
+        name="StarterPackLanding"
+        getComponent={() => StarterPackLandingScreen}
+      />
+      <Navigator.Group>
+        <Navigator.Screen
+          name="SelectAccount"
+          getComponent={() => SelectAccountScreen}
+        />
+        <Navigator.Screen name="SignIn" getComponent={() => SignInScreen} />
+        <Navigator.Screen
+          name="ForgotPassword"
+          getComponent={() => ForgotPasswordScreen}
+        />
+        <Navigator.Screen
+          name="SetNewPassword"
+          getComponent={() => SetNewPasswordScreen}
+        />
+        <Navigator.Screen
+          name="PasswordUpdated"
+          getComponent={() => PasswordUpdatedScreen}
+        />
+        <Navigator.Screen
+          name="SignUpInfo"
+          getComponent={() => SignUpInfoScreen}
+        />
+        <Navigator.Screen
+          name="SignUpHandle"
+          getComponent={() => SignUpHandleScreen}
+        />
+        <Navigator.Screen
+          name="SignUpCaptcha"
+          getComponent={() => SignUpCaptchaScreen}
+        />
+      </Navigator.Group>
+    </>
+  )
+}
+
 /**
  * The core navigator on native handles authentication, switching between
  * the main tab navigator when logged in and the auth screen when logged out.
@@ -800,48 +867,7 @@ export const NativeNavigator = () => {
           options={{animation: 'fade', animationDuration: 200}}
         />
       ) : (
-        <>
-          <Core.Screen
-            name="Landing"
-            getComponent={() => LandingScreen}
-            options={{animation: 'fade', animationDuration: 200}}
-          />
-          <Core.Screen
-            name="StarterPackLanding"
-            getComponent={() => StarterPackLandingScreen}
-          />
-          <Core.Group>
-            <Core.Screen
-              name="SelectAccount"
-              getComponent={() => SelectAccountScreen}
-            />
-            <Core.Screen name="SignIn" getComponent={() => SignInScreen} />
-            <Core.Screen
-              name="ForgotPassword"
-              getComponent={() => ForgotPasswordScreen}
-            />
-            <Core.Screen
-              name="SetNewPassword"
-              getComponent={() => SetNewPasswordScreen}
-            />
-            <Core.Screen
-              name="PasswordUpdated"
-              getComponent={() => PasswordUpdatedScreen}
-            />
-            <Core.Screen
-              name="SignUpInfo"
-              getComponent={() => SignUpInfoScreen}
-            />
-            <Core.Screen
-              name="SignUpHandle"
-              getComponent={() => SignUpHandleScreen}
-            />
-            <Core.Screen
-              name="SignUpCaptcha"
-              getComponent={() => SignUpCaptchaScreen}
-            />
-          </Core.Group>
-        </>
+        authScreens({navigator: Core as typeof Auth})
       )}
     </Core.Navigator>
   )
diff --git a/src/components/Layout/index.tsx b/src/components/Layout/index.tsx
index 5891ca863a..4be9fdc65d 100644
--- a/src/components/Layout/index.tsx
+++ b/src/components/Layout/index.tsx
@@ -13,6 +13,7 @@ import {useSafeAreaInsets} from 'react-native-safe-area-context'
 
 import {isWeb} from '#/platform/detection'
 import {useShellLayout} from '#/state/shell/shell-layout'
+import {useIsWithinAuthLayout} from '#/view/shell/desktop/AuthLayout'
 import {
   atoms as a,
   useBreakpoints,
@@ -38,16 +39,24 @@ export type ScreenProps = React.ComponentProps<typeof View> & {
 export const Screen = memo(function Screen({
   style,
   noInsetTop,
+  children,
   ...props
 }: ScreenProps) {
   const {top} = useSafeAreaInsets()
+  const withinAuthLayout = useIsWithinAuthLayout()
+
+  if (withinAuthLayout) {
+    return children
+  }
+
   return (
     <>
       {isWeb && <WebCenterBorders />}
       <View
         style={[a.util_screen_outer, {paddingTop: noInsetTop ? 0 : top}, style]}
-        {...props}
-      />
+        {...props}>
+        {children}
+      </View>
     </>
   )
 })
diff --git a/src/lib/routes/types.ts b/src/lib/routes/types.ts
index c1a63c48d2..252cf3cc9e 100644
--- a/src/lib/routes/types.ts
+++ b/src/lib/routes/types.ts
@@ -119,6 +119,7 @@ export type FlatNavigatorParams = CommonNavigatorParams & {
   Feeds: undefined
   Notifications: undefined
   Messages: {pushToConversation?: string; animation?: 'push' | 'pop'}
+  Auth: undefined
 }
 
 export type AllNavigatorParams = CommonNavigatorParams & {
diff --git a/src/routes.ts b/src/routes.ts
index 7fc673e2be..296b532ff5 100644
--- a/src/routes.ts
+++ b/src/routes.ts
@@ -3,7 +3,7 @@ import {type FlatNavigatorParams} from './lib/routes/types'
 
 type AllNavigatableRoutes = Omit<
   FlatNavigatorParams,
-  'NotFound' | 'SharedPreferencesTester'
+  'Auth' | 'NotFound' | 'SharedPreferencesTester'
 >
 
 export const router = new Router<AllNavigatableRoutes>({
diff --git a/src/view/shell/createNativeStackNavigatorWithAuth.tsx b/src/view/shell/createNativeStackNavigatorWithAuth.tsx
index 284dfea90e..323afa239f 100644
--- a/src/view/shell/createNativeStackNavigatorWithAuth.tsx
+++ b/src/view/shell/createNativeStackNavigatorWithAuth.tsx
@@ -1,4 +1,4 @@
-import * as React from 'react'
+import {useCallback, useEffect} from 'react'
 import {View} from 'react-native'
 // Based on @react-navigation/native-stack/src/navigators/createNativeStackNavigator.ts
 // MIT License
@@ -6,6 +6,7 @@ import {View} from 'react-native'
 import {
   createNavigatorFactory,
   type EventArg,
+  type NavigationProp,
   type NavigatorTypeBagBase,
   type ParamListBase,
   type StackActionHelpers,
@@ -15,6 +16,8 @@ import {
   type StackRouterOptions,
   type StaticConfig,
   type TypedNavigator,
+  useFocusEffect,
+  useNavigation,
   useNavigationBuilder,
 } from '@react-navigation/native'
 import {NativeStackView} from '@react-navigation/native-stack'
@@ -27,14 +30,11 @@ import {
 
 import {PWI_ENABLED} from '#/lib/build-flags'
 import {useWebMediaQueries} from '#/lib/hooks/useWebMediaQueries'
+import {type FlatNavigatorParams} from '#/lib/routes/types'
 import {isWeb} from '#/platform/detection'
 import {useSession} from '#/state/session'
 import {useOnboardingState} from '#/state/shell'
-import {
-  useLoggedOutView,
-  useLoggedOutViewControls,
-} from '#/state/shell/logged-out'
-import {LoggedOut} from '#/view/com/auth/LoggedOut'
+import {useLoggedOutView} from '#/state/shell/logged-out'
 import {Deactivated} from '#/screens/Deactivated'
 import {Onboarding} from '#/screens/Onboarding'
 import {SignupQueued} from '#/screens/SignupQueued'
@@ -76,7 +76,7 @@ function NativeStackNavigator({
       screenLayout,
     })
 
-  React.useEffect(
+  useEffect(
     () =>
       // @ts-expect-error: there may not be a tab navigator in parent
       navigation?.addListener?.('tabPress', (e: any) => {
@@ -108,23 +108,40 @@ function NativeStackNavigator({
   const activeDescriptor = descriptors[activeRoute.key]
   const activeRouteRequiresAuth = activeDescriptor.options.requireAuth ?? false
   const onboardingState = useOnboardingState()
-  const {showLoggedOut} = useLoggedOutView()
-  const {setShowLoggedOut} = useLoggedOutViewControls()
   const {isMobile} = useWebMediaQueries()
   const {leftNavMinimal} = useLayoutBreakpoints()
-  // Temp: use old system for web. TODO: unify
-  if (isWeb && !hasSession && (!PWI_ENABLED || activeRouteRequiresAuth)) {
-    return <LoggedOut />
-  }
+  const {showLoggedOut} = useLoggedOutView()
+
+  const shouldRedirectToAuth =
+    isWeb && activeRoute.name !== 'Auth' && (showLoggedOut || !PWI_ENABLED)
+  useEffect(() => {
+    if (shouldRedirectToAuth) {
+      navigation.navigate('Auth')
+    }
+  }, [navigation, shouldRedirectToAuth])
+
+  const shouldRedirectAwayFromAuth =
+    isWeb &&
+    activeRoute.name === 'Auth' &&
+    !showLoggedOut &&
+    PWI_ENABLED &&
+    !activeRouteRequiresAuth
+  useEffect(() => {
+    if (shouldRedirectAwayFromAuth) {
+      if (navigation.canGoBack()) {
+        navigation.goBack()
+      } else {
+        navigation.replace('Home')
+      }
+    }
+  }, [navigation, shouldRedirectAwayFromAuth])
+
   if (hasSession && currentAccount?.signupQueued) {
     return <SignupQueued />
   }
   if (hasSession && currentAccount?.status === 'takendown') {
     return <Takendown />
   }
-  if (isWeb && showLoggedOut) {
-    return <LoggedOut onDismiss={() => setShowLoggedOut(false)} />
-  }
   if (currentAccount?.status === 'deactivated') {
     return <Deactivated />
   }
@@ -139,7 +156,7 @@ function NativeStackNavigator({
       ...descriptor,
       render() {
         if (requireAuth && !hasSession) {
-          return <View />
+          return <RedirectToAuth />
         } else {
           return descriptor.render()
         }
@@ -158,7 +175,7 @@ function NativeStackNavigator({
           {...rest}
           state={state}
           navigation={navigation}
-          descriptors={descriptors}
+          descriptors={newDescriptors}
           describe={describe}
         />
       </View>
@@ -172,6 +189,25 @@ function NativeStackNavigator({
   )
 }
 
+/**
+ * Redirects to the auth screen on web. On native, this is handled by swapping
+ * out the screens instead - see `NativeNavigator`
+ */
+function RedirectToAuth() {
+  const navigation = useNavigation<NavigationProp<FlatNavigatorParams>>()
+  useFocusEffect(
+    useCallback(() => {
+      if (isWeb) {
+        const timeout = setTimeout(() => {
+          navigation.navigate('Auth')
+        }, 500)
+        return () => clearTimeout(timeout)
+      }
+    }, [navigation]),
+  )
+  return <View />
+}
+
 export function createNativeStackNavigatorWithAuth<
   const ParamList extends ParamListBase,
   const NavigatorID extends string | undefined = undefined,
diff --git a/src/view/shell/desktop/AuthLayout.native.tsx b/src/view/shell/desktop/AuthLayout.native.tsx
new file mode 100644
index 0000000000..727c2a7406
--- /dev/null
+++ b/src/view/shell/desktop/AuthLayout.native.tsx
@@ -0,0 +1,7 @@
+export function AuthLayout({children}: {children: React.ReactNode}) {
+  return children
+}
+
+export function useIsWithinAuthLayout() {
+  return false
+}
diff --git a/src/view/shell/desktop/AuthLayout.tsx b/src/view/shell/desktop/AuthLayout.tsx
new file mode 100644
index 0000000000..90ea576ab7
--- /dev/null
+++ b/src/view/shell/desktop/AuthLayout.tsx
@@ -0,0 +1,119 @@
+import {createContext, useContext} from 'react'
+import {Pressable, View} from 'react-native'
+import {msg} from '@lingui/macro'
+import {useLingui} from '@lingui/react'
+import {DismissableLayer, FocusGuards, FocusScope} from 'radix-ui/internal'
+import {createPortal} from 'react-dom'
+import {RemoveScrollBar} from 'react-remove-scroll-bar'
+
+import {useA11y} from '#/state/a11y'
+import {useLoggedOutViewControls} from '#/state/shell/logged-out'
+import {atoms as a, flatten, useTheme, web} from '#/alf'
+
+const stopPropagation = (e: any) => e.stopPropagation()
+const preventDefault = (e: any) => e.preventDefault()
+
+const WithinAuthLayoutContext = createContext(false)
+
+export function AuthModal({children}: {children: React.ReactNode}) {
+  const t = useTheme()
+  const {_} = useLingui()
+  const {reduceMotionEnabled} = useA11y()
+  const {setShowLoggedOut} = useLoggedOutViewControls()
+  FocusGuards.useFocusGuards()
+
+  console.log('auth modal')
+
+  return createPortal(
+    <Pressable
+      accessibilityLabel={_(msg`Close active dialog`)}
+      accessibilityHint={undefined}
+      onPress={() => setShowLoggedOut(false)}>
+      <RemoveScrollBar />
+      <View
+        style={[
+          a.fixed,
+          a.inset_0,
+          a.z_10,
+          a.px_xl,
+          a.align_center,
+          a.justify_center,
+          web({overflowY: 'auto'}),
+          {zIndex: 999999},
+        ]}>
+        <Backdrop />
+        <View
+          style={[
+            a.w_full,
+            a.z_20,
+            a.align_center,
+            web({minHeight: '60vh', position: 'static'}),
+          ]}>
+          <FocusScope.FocusScope loop asChild trapped>
+            <View
+              role="dialog"
+              aria-role="dialog"
+              aria-label={_(msg`Log in or sign up`)}
+              // @ts-expect-error web only -prf
+              onClick={stopPropagation}
+              onStartShouldSetResponder={_ => true}
+              onTouchEnd={stopPropagation}
+              style={flatten([
+                a.relative,
+                a.rounded_md,
+                a.w_full,
+                a.border,
+                t.atoms.bg,
+                {
+                  minHeight: '100%',
+                  maxWidth: 600,
+                  borderColor: t.palette.contrast_200,
+                  shadowColor: t.palette.black,
+                  shadowOpacity: t.name === 'light' ? 0.1 : 0.4,
+                  shadowRadius: 30,
+                },
+                !reduceMotionEnabled && a.zoom_fade_in,
+                a.p_xl,
+              ])}>
+              <DismissableLayer.DismissableLayer
+                onInteractOutside={preventDefault}
+                onFocusOutside={preventDefault}
+                onDismiss={close}
+                style={{
+                  display: 'flex',
+                  flexDirection: 'column',
+                  flex: '1 1 0',
+                }}>
+                <WithinAuthLayoutContext.Provider value={true}>
+                  {children}
+                </WithinAuthLayoutContext.Provider>
+              </DismissableLayer.DismissableLayer>
+            </View>
+          </FocusScope.FocusScope>
+        </View>
+      </View>
+    </Pressable>,
+    document.querySelector('#root')!,
+  )
+}
+
+function Backdrop() {
+  const t = useTheme()
+  const {reduceMotionEnabled} = useA11y()
+  return (
+    <View style={{opacity: 0.8}}>
+      <View
+        style={[
+          a.fixed,
+          a.inset_0,
+          {backgroundColor: t.palette.black},
+          !reduceMotionEnabled && a.fade_in,
+        ]}
+      />
+    </View>
+  )
+}
+
+export function useIsWithinAuthLayout() {
+  return useContext(WithinAuthLayoutContext)
+}