diff --git a/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/android/src/main/java/NativeBridgePlugin.kt b/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/android/src/main/java/NativeBridgePlugin.kt
index 83c8681a..c4a2dcb0 100644
--- a/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/android/src/main/java/NativeBridgePlugin.kt
+++ b/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/android/src/main/java/NativeBridgePlugin.kt
@@ -495,13 +495,19 @@ class NativeBridgePlugin(private val activity: Activity): Plugin(activity) {
         val args = invoke.parseArgs(SetScreenBrightnessRequestArgs::class.java)
         val ret = JSObject()
         try {
-            val brightness = (args.brightness ?: 0.5).toFloat()
-            if (brightness < 0.0 || brightness > 1.0) {
-                invoke.reject("Brightness must be between 0.0 and 1.0")
-                return
-            }
+            val brightness = args.brightness?.toFloat()
             val layoutParams = activity.window.attributes
-            layoutParams.screenBrightness = brightness
+
+            if (brightness == null || brightness < 0.0) {
+                layoutParams.screenBrightness = WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_NONE
+            } else {
+                if (brightness > 1.0) {
+                    invoke.reject("Brightness must be between 0.0 and 1.0, or null to use system brightness")
+                    return
+                }
+                layoutParams.screenBrightness = brightness
+            }
+
             activity.window.attributes = layoutParams
             ret.put("success", true)
         } catch (e: Exception) {
diff --git a/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/ios/Sources/NativeBridgePlugin.swift b/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/ios/Sources/NativeBridgePlugin.swift
index ba4fc6d4..4bffe764 100644
--- a/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/ios/Sources/NativeBridgePlugin.swift
+++ b/apps/readest-app/src-tauri/plugins/tauri-plugin-native-bridge/ios/Sources/NativeBridgePlugin.swift
@@ -812,7 +812,13 @@ class NativeBridgePlugin: Plugin {
 
     let brightness = args.brightness ?? 0.5
 
-    if brightness < 0.0 || brightness > 1.0 {
+    if brightness < 0.0 {
+      // Revert to system brightness - iOS doesn't have a direct "system brightness" setting
+      // We will restore the brightness that was set before the app modified it
+      return invoke.resolve(["success": true])
+    }
+
+    if brightness > 1.0 {
       return invoke.reject("Brightness must be between 0.0 and 1.0")
     }
 
diff --git a/apps/readest-app/src/app/reader/components/Reader.tsx b/apps/readest-app/src/app/reader/components/Reader.tsx
index dcd31dcc..3cf85b4c 100644
--- a/apps/readest-app/src/app/reader/components/Reader.tsx
+++ b/apps/readest-app/src/app/reader/components/Reader.tsx
@@ -52,9 +52,10 @@ Z-Index Layering Guide:
 const Reader: React.FC<{ ids?: string }> = ({ ids }) => {
   const router = useRouter();
   const { appService } = useEnv();
-  const { hoveredBookKey, getView } = useReaderStore();
   const { settings } = useSettingsStore();
   const { sideBarBookKey } = useSidebarStore();
+  const { hoveredBookKey, getView } = useReaderStore();
+  const { getScreenBrightness, setScreenBrightness } = useDeviceControlStore();
   const { isSideBarVisible, getIsSideBarVisible, setSideBarVisible } = useSidebarStore();
   const { isNotebookVisible, getIsNotebookVisible, setNotebookVisible } = useNotebookStore();
   const { isDarkMode, systemUIAlwaysHidden, isRoundedWindow } = useThemeStore();
@@ -74,6 +75,27 @@ const Reader: React.FC<{ ids?: string }> = ({ ids }) => {
     initDayjs(getLocale());
   }, []);
 
+  useEffect(() => {
+    const brightness = settings.screenBrightness;
+    const autoBrightness = settings.autoScreenBrightness;
+    if (appService?.hasScreenBrightness && !autoBrightness && brightness >= 0) {
+      setScreenBrightness(brightness / 100);
+    }
+    let previousBrightness = -1;
+    if (appService?.isIOSApp) {
+      getScreenBrightness().then((b) => {
+        previousBrightness = b;
+      });
+    }
+
+    return () => {
+      if (appService?.hasScreenBrightness && !autoBrightness) {
+        setScreenBrightness(previousBrightness);
+      }
+    };
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [appService]);
+
   const handleKeyDown = (event: CustomEvent) => {
     const view = getView(sideBarBookKey!);
     if (event.detail.keyName === 'Back') {
diff --git a/apps/readest-app/src/components/Providers.tsx b/apps/readest-app/src/components/Providers.tsx
index 01bebb41..fd89c3fb 100644
--- a/apps/readest-app/src/components/Providers.tsx
+++ b/apps/readest-app/src/components/Providers.tsx
@@ -10,7 +10,6 @@ import { CSPostHogProvider } from '@/context/PHContext';
 import { SyncProvider } from '@/context/SyncContext';
 import { initSystemThemeListener, loadDataTheme } from '@/store/themeStore';
 import { useSettingsStore } from '@/store/settingsStore';
-import { useDeviceControlStore } from '@/store/deviceStore';
 import { useSafeAreaInsets } from '@/hooks/useSafeAreaInsets';
 import { useDefaultIconSize } from '@/hooks/useResponsiveSize';
 import { useBackgroundTexture } from '@/hooks/useBackgroundTexture';
@@ -21,7 +20,6 @@ import { getDirFromUILanguage } from '@/utils/rtl';
 const Providers = ({ children }: { children: React.ReactNode }) => {
   const { envConfig, appService } = useEnv();
   const { applyUILanguage } = useSettingsStore();
-  const { setScreenBrightness } = useDeviceControlStore();
   const { applyBackgroundTexture } = useBackgroundTexture();
   const { applyEinkMode } = useEinkMode();
   const iconSize = useDefaultIconSize();
@@ -54,25 +52,13 @@ const Providers = ({ children }: { children: React.ReactNode }) => {
       appService.loadSettings().then((settings) => {
         const globalViewSettings = settings.globalViewSettings;
         applyUILanguage(globalViewSettings.uiLanguage);
-        const brightness = settings.screenBrightness;
-        const autoBrightness = settings.autoScreenBrightness;
-        if (appService.hasScreenBrightness && !autoBrightness && brightness >= 0) {
-          setScreenBrightness(brightness / 100);
-        }
         applyBackgroundTexture(envConfig, globalViewSettings);
         if (globalViewSettings.isEink) {
           applyEinkMode(true);
         }
       });
     }
-  }, [
-    envConfig,
-    appService,
-    applyUILanguage,
-    setScreenBrightness,
-    applyBackgroundTexture,
-    applyEinkMode,
-  ]);
+  }, [envConfig, appService, applyUILanguage, applyBackgroundTexture, applyEinkMode]);
 
   // Make sure appService is available in all children components
   if (!appService) return;