diff --git a/BitFun-Installer/src-tauri/src/installer/types.rs b/BitFun-Installer/src-tauri/src/installer/types.rs
index 27b3539f..5e8080f1 100644
--- a/BitFun-Installer/src-tauri/src/installer/types.rs
+++ b/BitFun-Installer/src-tauri/src/installer/types.rs
@@ -93,7 +93,7 @@ impl Default for InstallOptions {
             add_to_path: true,
             launch_after_install: true,
             app_language: "zh-CN".to_string(),
-            theme_preference: "bitfun-dark".to_string(),
+            theme_preference: "bitfun-light".to_string(),
             model_config: None,
         }
     }
diff --git a/BitFun-Installer/src/pages/ThemeSetup.tsx b/BitFun-Installer/src/pages/ThemeSetup.tsx
index 6d0a349d..fa293cad 100644
--- a/BitFun-Installer/src/pages/ThemeSetup.tsx
+++ b/BitFun-Installer/src/pages/ThemeSetup.tsx
@@ -155,9 +155,9 @@ const THEMES: InstallerTheme[] = [
 ];
 
 const THEME_DISPLAY_ORDER: ThemeId[] = [
+  'bitfun-light',
   'bitfun-slate',
   'bitfun-dark',
-  'bitfun-light',
   'bitfun-midnight',
   'bitfun-china-style',
   'bitfun-china-night',
@@ -223,7 +223,10 @@ export function ThemeSetup({ options, setOptions, onLaunch, onClose }: ThemeSetu
   };
 
   useEffect(() => {
-    const selectedTheme = THEMES.find((theme) => theme.id === options.themePreference) ?? THEMES[0];
+    const selectedTheme =
+      THEMES.find((theme) => theme.id === options.themePreference) ??
+      THEMES.find((theme) => theme.id === 'bitfun-light') ??
+      THEMES[0];
     const root = document.documentElement;
     const { colors } = selectedTheme;
 
diff --git a/BitFun-Installer/src/types/installer.ts b/BitFun-Installer/src/types/installer.ts
index 6df2d13f..ac0fb18e 100644
--- a/BitFun-Installer/src/types/installer.ts
+++ b/BitFun-Installer/src/types/installer.ts
@@ -77,6 +77,6 @@ export const DEFAULT_OPTIONS: InstallOptions = {
   addToPath: true,
   launchAfterInstall: true,
   appLanguage: 'zh-CN',
-  themePreference: 'bitfun-slate',
+  themePreference: 'bitfun-light',
   modelConfig: null,
 };
diff --git a/src/apps/desktop/src/theme.rs b/src/apps/desktop/src/theme.rs
index 2d5238a7..3ad736d6 100644
--- a/src/apps/desktop/src/theme.rs
+++ b/src/apps/desktop/src/theme.rs
@@ -19,15 +19,15 @@ pub struct ThemeConfig {
 
 impl Default for ThemeConfig {
     fn default() -> Self {
-        Self::get_builtin_theme("bitfun-slate").unwrap_or_else(|| Self {
-            id: "bitfun-slate".to_string(),
-            bg_primary: "#1a1c1e".to_string(),
-            bg_secondary: "#1a1c1e".to_string(),
-            bg_scene: "#1d2023".to_string(),
-            is_light: false,
-            text_primary: "#e4e6e8".to_string(),
-            text_muted: "#8a8d92".to_string(),
-            accent_color: "#6b9bd5".to_string(),
+        Self::get_builtin_theme("bitfun-light").unwrap_or_else(|| Self {
+            id: "bitfun-light".to_string(),
+            bg_primary: "#f4f4f4".to_string(),
+            bg_secondary: "#ffffff".to_string(),
+            bg_scene: "#ffffff".to_string(),
+            is_light: true,
+            text_primary: "#111827".to_string(),
+            text_muted: "rgba(0, 0, 0, 0.5)".to_string(),
+            accent_color: "#3b82f6".to_string(),
         })
     }
 }
@@ -145,7 +145,7 @@ impl ThemeConfig {
             .themes
             .as_ref()
             .map(|t| t.current.as_str())
-            .unwrap_or("bitfun-slate");
+            .unwrap_or("bitfun-light");
 
         match Self::get_builtin_theme(theme_id) {
             Some(config) => config,
diff --git a/src/crates/core/src/service/config/types.rs b/src/crates/core/src/service/config/types.rs
index 3a6c51da..cd08164a 100644
--- a/src/crates/core/src/service/config/types.rs
+++ b/src/crates/core/src/service/config/types.rs
@@ -194,7 +194,7 @@ pub struct ThemesConfig {
 impl Default for ThemesConfig {
     fn default() -> Self {
         Self {
-            current: "bitfun-slate".to_string(),
+            current: "bitfun-light".to_string(),
             custom: None,
         }
     }
@@ -1067,7 +1067,7 @@ impl Default for EditorConfig {
                 side: "right".to_string(),
                 size: "proportional".to_string(),
             },
-            theme: "vs-dark".to_string(),
+            theme: "vs".to_string(),
             auto_save: "afterDelay".to_string(),
             auto_save_delay: 1000,
             format_on_save: true,
diff --git a/src/web-ui/src/features/onboarding/components/steps/ThemeStep.tsx b/src/web-ui/src/features/onboarding/components/steps/ThemeStep.tsx
index 1b4f6084..cc94d780 100644
--- a/src/web-ui/src/features/onboarding/components/steps/ThemeStep.tsx
+++ b/src/web-ui/src/features/onboarding/components/steps/ThemeStep.tsx
@@ -15,16 +15,16 @@ interface ThemeStepProps {
 }
 
 const THEME_OPTIONS = [
-  { 
-    id: 'bitfun-dark', 
-    nameKey: 'theme.themes.bitfun-dark.name',
-    descKey: 'theme.themes.bitfun-dark.description'
-  },
   { 
     id: 'bitfun-light', 
     nameKey: 'theme.themes.bitfun-light.name',
     descKey: 'theme.themes.bitfun-light.description'
   },
+  { 
+    id: 'bitfun-dark', 
+    nameKey: 'theme.themes.bitfun-dark.name',
+    descKey: 'theme.themes.bitfun-dark.description'
+  },
   { 
     id: 'bitfun-midnight', 
     nameKey: 'theme.themes.bitfun-midnight.name',
diff --git a/src/web-ui/src/features/onboarding/store/onboardingStore.ts b/src/web-ui/src/features/onboarding/store/onboardingStore.ts
index 1451b378..1d02ecda 100644
--- a/src/web-ui/src/features/onboarding/store/onboardingStore.ts
+++ b/src/web-ui/src/features/onboarding/store/onboardingStore.ts
@@ -94,7 +94,7 @@ export const useOnboardingStore = create<OnboardingState>()(
       skipped: false,
       
       selectedLanguage: 'zh-CN',
-      selectedTheme: 'bitfun-dark',
+      selectedTheme: 'bitfun-light',
       modelConfig: null,
       
       // Start onboarding
diff --git a/src/web-ui/src/infrastructure/theme/presets/index.ts b/src/web-ui/src/infrastructure/theme/presets/index.ts
index c3f66b6d..41c4108f 100644
--- a/src/web-ui/src/infrastructure/theme/presets/index.ts
+++ b/src/web-ui/src/infrastructure/theme/presets/index.ts
@@ -29,7 +29,7 @@ export const builtinThemes: ThemeConfig[] = [
 ];
 
  
-export const DEFAULT_THEME_ID = 'bitfun-slate';
+export const DEFAULT_THEME_ID = 'bitfun-light';