diff --git a/CustomKeyboard/KeyboardViewController.m b/CustomKeyboard/KeyboardViewController.m
index 353a9ae..69e0602 100644
--- a/CustomKeyboard/KeyboardViewController.m
+++ b/CustomKeyboard/KeyboardViewController.m
@@ -16,6 +16,7 @@
 #import "KBKeyBoardMainView.h"
 #import "KBKeyboardSubscriptionView.h"
 #import "KBLocalizationManager.h"
+#import "KBSettingView.h"
 #import "KBSkinManager.h"
 #import "KBSkinInstallBridge.h"
 #import "KBSuggestionEngine.h"
@@ -96,6 +97,19 @@ static NSString *KBFormatMB(uint64_t bytes) {
                 }
                 [self kb_applyTheme];
               }];
+
+  // 语言变化时，重建键盘 UI（保证“App 语言=键盘语言”，并支持 App 内切换语言后键盘即时刷新）
+  self.kb_localizationObserverToken = [[NSNotificationCenter defaultCenter]
+      addObserverForName:KBLocalizationDidChangeNotification
+                  object:nil
+                   queue:[NSOperationQueue mainQueue]
+              usingBlock:^(__unused NSNotification *_Nonnull note) {
+                __strong typeof(weakSelf) self = weakSelf;
+                if (!self) {
+                  return;
+                }
+                [self kb_reloadUIForLocalizationChange];
+              }];
   [self kb_applyTheme];
   [self kb_registerDarwinSkinInstallObserver];
   [self kb_consumePendingShopSkin];
@@ -239,6 +253,11 @@ static NSString *KBFormatMB(uint64_t bytes) {
         removeObserver:self.kb_skinObserverToken];
     self.kb_skinObserverToken = nil;
   }
+  if (self.kb_localizationObserverToken) {
+    [[NSNotificationCenter defaultCenter]
+        removeObserver:self.kb_localizationObserverToken];
+    self.kb_localizationObserverToken = nil;
+  }
   [self kb_stopObservingAppGroupChanges];
   [self kb_unregisterDarwinSkinInstallObserver];
 #if DEBUG
@@ -250,6 +269,57 @@ static NSString *KBFormatMB(uint64_t bytes) {
 #endif
 }
 
+#pragma mark - Localization
+
+- (void)kb_reloadUIForLocalizationChange {
+  if (![NSThread isMainThread]) {
+    __weak typeof(self) weakSelf = self;
+    dispatch_async(dispatch_get_main_queue(), ^{
+      [weakSelf kb_reloadUIForLocalizationChange];
+    });
+    return;
+  }
+
+  // 记录当前面板状态，重建后尽量恢复。
+  KBKeyboardPanelMode targetMode = self.kb_panelMode;
+  // 强制下次布局刷新：即使 profileId 未变，也需要让新建的主视图应用一次当前 profile。
+  _kb_lastLoadedProfileId = nil;
+
+  // 主键盘/面板里有大量静态文案（init 时设置），语言变化后需要重建才能刷新。
+  if (_keyBoardMainView) {
+    [_keyBoardMainView removeFromSuperview];
+    _keyBoardMainView = nil;
+  }
+  self.keyBoardMainHeightConstraint = nil;
+
+  if (_functionView) {
+    [_functionView removeFromSuperview];
+    _functionView = nil;
+  }
+  if (_settingView) {
+    [_settingView removeFromSuperview];
+    _settingView = nil;
+  }
+  if (_subscriptionView) {
+    [_subscriptionView removeFromSuperview];
+    _subscriptionView = nil;
+  }
+  if (_chatPanelView) {
+    [_chatPanelView removeFromSuperview];
+    _chatPanelView = nil;
+  }
+  self.chatPanelVisible = NO;
+  self.chatPanelHeightConstraint = nil;
+
+  // 强制触发面板刷新：先回到 Main，再切回目标面板（避免 kb_setPanelMode 直接 return）。
+  self.kb_panelMode = KBKeyboardPanelModeMain;
+  [self kb_setPanelMode:targetMode animated:NO];
+  // 语言变化后，键盘布局/profile 也可能需要同步更新（未手动选择键盘配置时会随 App 语言变化）
+  [self kb_checkAndApplyLayoutIfNeeded];
+  [KBHUD setContainerView:self.view];
+  [self kb_applyTheme];
+}
+
 #pragma mark - Layout Switching
 
 - (void)kb_checkAndApplyLayoutIfNeeded {
diff --git a/CustomKeyboard/KeyboardViewControllerHelp/KeyboardViewController+Private.h b/CustomKeyboard/KeyboardViewControllerHelp/KeyboardViewController+Private.h
index 2efebb2..30f388a 100644
--- a/CustomKeyboard/KeyboardViewControllerHelp/KeyboardViewController+Private.h
+++ b/CustomKeyboard/KeyboardViewControllerHelp/KeyboardViewController+Private.h
@@ -68,6 +68,7 @@ typedef NS_ENUM(NSInteger, KBKeyboardPanelMode) {
   NSString *_chatPanelBaselineText;
   id _kb_fullAccessObserverToken;
   id _kb_skinObserverToken;
+  id _kb_localizationObserverToken;
   KBKeyboardPanelMode _kb_panelMode;
 }
 
@@ -104,6 +105,7 @@ typedef NS_ENUM(NSInteger, KBKeyboardPanelMode) {
 @property(nonatomic, copy) NSString *chatPanelBaselineText; // 打开聊天面板时宿主输入框已有的文本
 @property(nonatomic, strong, nullable) id kb_fullAccessObserverToken;
 @property(nonatomic, strong, nullable) id kb_skinObserverToken;
+@property(nonatomic, strong, nullable) id kb_localizationObserverToken;
 @property(nonatomic, assign) KBKeyboardPanelMode kb_panelMode;
 @property(nonatomic, strong, nullable) id kb_appGroupObserverToken;
 
diff --git a/CustomKeyboard/Manager/KBKeyboardLayoutResolver.m b/CustomKeyboard/Manager/KBKeyboardLayoutResolver.m
index 581c5fd..d082f44 100644
--- a/CustomKeyboard/Manager/KBKeyboardLayoutResolver.m
+++ b/CustomKeyboard/Manager/KBKeyboardLayoutResolver.m
@@ -6,6 +6,7 @@
 #import "KBKeyboardLayoutResolver.h"
 #import "KBInputProfileManager.h"
 #import "KBConfig.h"
+#import "KBLocalizationManager.h"
 
 @implementation KBKeyboardLayoutResolver
 
@@ -18,6 +19,30 @@
     return instance;
 }
 
+/// 未手动选择键盘输入配置时，根据当前 App 语言推导默认键盘语言码（对应 kb_input_profiles.json 的 code）。
+- (NSString *)kb_defaultKeyboardLanguageCodeForAppLanguageCode:(NSString *)appLanguageCode {
+    NSString *lc = (appLanguageCode ?: @"").lowercaseString;
+    if ([lc hasPrefix:@"es"]) { return @"es"; }
+    if ([lc hasPrefix:@"pt"]) { return @"pt"; }
+    if ([lc hasPrefix:@"id"]) { return @"id"; }
+    if ([lc hasPrefix:@"zh-hant"]) { return @"zh-Hant-Pinyin"; }
+    return @"en";
+}
+
+- (BOOL)kb_didUserSelectKeyboardProfileInAppGroup:(NSUserDefaults *)appGroup {
+    return [appGroup boolForKey:AppGroup_DidUserSelectKeyboardProfile];
+}
+
+- (nullable KBInputProfileLayout *)kb_defaultLayoutForCurrentAppLanguage {
+    NSString *appLang = [KBLocalizationManager shared].currentLanguageCode ?: KBLanguageCodeEnglish;
+    NSString *kbLang = [self kb_defaultKeyboardLanguageCodeForAppLanguageCode:appLang];
+    KBInputProfile *profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:kbLang];
+    if (!profile) {
+        profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:@"en"];
+    }
+    return profile.layouts.firstObject;
+}
+
 - (NSString *)layoutJsonIdForProfileId:(NSString *)profileId {
     if (profileId.length == 0) {
         return @"letters";
@@ -51,19 +76,31 @@
 - (nullable NSString *)currentProfileId {
     NSUserDefaults *appGroup = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
     NSString *profileId = [appGroup stringForKey:AppGroup_SelectedKeyboardProfileId];
-    return profileId;
+    if ([self kb_didUserSelectKeyboardProfileInAppGroup:appGroup]) {
+        return profileId;
+    }
+    KBInputProfileLayout *layout = [self kb_defaultLayoutForCurrentAppLanguage];
+    return layout.profileId.length > 0 ? layout.profileId : profileId;
 }
 
 - (nullable NSString *)currentLanguageCode {
     NSUserDefaults *appGroup = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
     NSString *languageCode = [appGroup stringForKey:AppGroup_SelectedKeyboardLanguageCode];
-    return languageCode;
+    if ([self kb_didUserSelectKeyboardProfileInAppGroup:appGroup]) {
+        return languageCode;
+    }
+    NSString *appLang = [KBLocalizationManager shared].currentLanguageCode ?: KBLanguageCodeEnglish;
+    return [self kb_defaultKeyboardLanguageCodeForAppLanguageCode:appLang];
 }
 
 - (nullable NSString *)currentLayoutVariant {
     NSUserDefaults *appGroup = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
     NSString *layoutVariant = [appGroup stringForKey:AppGroup_SelectedKeyboardLayoutVariant];
-    return layoutVariant;
+    if ([self kb_didUserSelectKeyboardProfileInAppGroup:appGroup]) {
+        return layoutVariant;
+    }
+    KBInputProfileLayout *layout = [self kb_defaultLayoutForCurrentAppLanguage];
+    return layout.variant.length > 0 ? layout.variant : layoutVariant;
 }
 
 @end
diff --git a/CustomKeyboard/Resource/kb_keyboard_layout_config.json b/CustomKeyboard/Resource/kb_keyboard_layout_config.json
index 34a5be2..dd957f8 100644
--- a/CustomKeyboard/Resource/kb_keyboard_layout_config.json
+++ b/CustomKeyboard/Resource/kb_keyboard_layout_config.json
@@ -843,7 +843,7 @@
           "align": "left",
           "insetLeft": 4,
           "insetRight": 4,
-          "gap": 5,
+          "gap": 6,
           "items": [
             "letter:ㄅ", "letter:ㄉ", "letter:ˇ", "letter:ˋ", "letter:ㄓ",
             "letter:ˊ", "letter:˙", "letter:ㄚ", "letter:ㄞ", "letter:ㄢ", "letter:ㄦ"
diff --git a/Shared/KBConfig.h b/Shared/KBConfig.h
index 1364bf4..4541a94 100644
--- a/Shared/KBConfig.h
+++ b/Shared/KBConfig.h
@@ -38,6 +38,11 @@
 #define AppGroup_SelectedKeyboardLanguageCode @"AppGroup_SelectedKeyboardLanguageCode"
 #define AppGroup_SelectedKeyboardLayoutVariant @"AppGroup_SelectedKeyboardLayoutVariant"
 
+/// 是否用户手动选择过键盘输入配置（语言/布局/profile）。
+/// YES：主 App 不再自动把键盘配置跟随 App 语言变更（避免覆盖用户手选）。
+/// NO ：主 App 会在“App 语言变化且未手动选择键盘配置”时同步更新键盘配置，使键盘语言/布局与 App 一致。
+#define AppGroup_DidUserSelectKeyboardProfile @"AppGroup_DidUserSelectKeyboardProfile"
+
 /// Darwin 跨进程通知：键盘扩展发送聊天消息后通知主 App 刷新
 #define kKBDarwinChatUpdated @"com.loveKey.nyx.chat.updated"
 
diff --git a/Shared/KBLocalizationManager.m b/Shared/KBLocalizationManager.m
index 92e8115..07be3a9 100644
--- a/Shared/KBLocalizationManager.m
+++ b/Shared/KBLocalizationManager.m
@@ -7,6 +7,9 @@
 #import <Security/Security.h>
 #import "KBConfig.h"
 
+// Darwin 跨进程通知：语言变更（App <-> 扩展）
+static NSString * const kKBDarwinLocalizationChanged = @"com.loveKey.nyx.loc.changed";
+
 /// 语言常量定义
 KBLanguageCode const KBLanguageCodeEnglish           = @"en";
 KBLanguageCode const KBLanguageCodeTraditionalChinese = @"zh-Hant";
@@ -37,9 +40,20 @@ NSString * const KBLocalizationDidChangeNotification = @"KBLocalizationDidChange
 static NSString * const kKBLocService = @"com.loveKey.nyx.loc";
 static NSString * const kKBLocAccount = @"lang"; // 保存 UTF8 的语言代码
 
+// 首次安装/首次启动标记（仅主 App 侧使用标准 UserDefaults；卸载后会被清除，用于抵消 Keychain 在卸载重装后仍保留的问题）
+static NSString * const kKBLocDidLaunchKey = @"com.loveKey.nyx.loc.did_launch";
+// 主 App 启动标记（存 App Group，键盘扩展可读）：用于“扩展先启动”场景下避免读取卸载重装遗留的 Keychain 语言。
+static NSString * const kKBLocAppBootstrappedKey = @"com.loveKey.nyx.loc.app_bootstrapped";
+// 用户是否在 App 内手动选择过语言（存 App Group；卸载重装会清理，满足“重装后跟随系统”）
+static NSString * const kKBLocUserSelectedLanguageKey = @"com.loveKey.nyx.loc.user_selected_language";
+
 @interface KBLocalizationManager ()
 @property (nonatomic, copy, readwrite) KBLanguageCode currentLanguageCode; // 当前语言代码
 @property (nonatomic, strong) NSBundle *langBundle; // 对应语言的 .lproj 资源包
+
+- (NSString *)normalizeLanguageCode:(NSString *)code;
+- (NSString *)supportedLanguageCodeForCandidate:(nullable NSString *)code;
+- (void)kb_onSystemLocaleMaybeChanged:(NSNotification *)note;
 @end
 
 // 避免 +shared 初始化阶段递归触发自身：
@@ -54,19 +68,141 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
     return q;
 }
 
+static void KBLocDarwinCallback(CFNotificationCenterRef center,
+                                void *observer,
+                                CFStringRef name,
+                                const void *object,
+                                CFDictionaryRef userInfo) {
+    // 语言更新后，扩展侧需要主动 reload；App 侧收到也无害（会被 resolved==current short-circuit）。
+    dispatch_async(dispatch_get_main_queue(), ^{
+        KBLocalizationManager *m = [KBLocalizationManager shared];
+        [m reloadFromSharedStorageIfNeeded];
+    });
+}
+
 @implementation KBLocalizationManager
 
+/// 是否运行在 App Extension（如键盘扩展）里。
+/// 说明：扩展与主 App 共享 Keychain，但不应参与“首次启动”判定，避免扩展抢先写入标记导致主 App 不再清理历史 Keychain。
++ (BOOL)kb_isRunningInAppExtension {
+    return ([[NSBundle mainBundle] objectForInfoDictionaryKey:@"NSExtension"] != nil);
+}
+
++ (NSUserDefaults *)kb_appGroupUserDefaults {
+    NSUserDefaults *ud = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
+    return ud ?: [NSUserDefaults standardUserDefaults];
+}
+
++ (BOOL)kb_isAppBootstrapped {
+    // App Group 在卸载重装后会被清理；扩展通过该标记判断“主 App 是否已在本次安装中启动过”。
+    return [[self kb_appGroupUserDefaults] boolForKey:kKBLocAppBootstrappedKey];
+}
+
++ (void)kb_markAppBootstrappedIfNeeded {
+    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
+    if ([ud boolForKey:kKBLocAppBootstrappedKey]) { return; }
+    [ud setBool:YES forKey:kKBLocAppBootstrappedKey];
+    [ud synchronize];
+}
+
++ (BOOL)kb_userDidSelectLanguage {
+    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
+    return [ud boolForKey:kKBLocUserSelectedLanguageKey];
+}
+
++ (void)kb_setUserDidSelectLanguage:(BOOL)selected {
+    NSUserDefaults *ud = [self kb_appGroupUserDefaults];
+    [ud setBool:selected forKey:kKBLocUserSelectedLanguageKey];
+    [ud synchronize];
+}
+
 + (instancetype)shared {
     static KBLocalizationManager *m; static dispatch_once_t onceToken; dispatch_once(&onceToken, ^{
         m = [KBLocalizationManager new];
         // 默认支持语言；可在启动时由外部重置
         m.supportedLanguageCodes = KBDefaultSupportedLanguageCodes();
-        // 启动读取：先取共享钥匙串，再按系统偏好回退
-        NSString *saved = [[self class] kc_read];
-        if (saved.length == 0) {
-            saved = [m bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
+        
+        BOOL isAppExtension = [[self class] kb_isRunningInAppExtension];
+        BOOL wasAppBootstrapped = [[self class] kb_isAppBootstrapped];
+        BOOL isAppBootstrapped = wasAppBootstrapped;
+        if (!isAppExtension) {
+            // 仅主 App 写入该标记；扩展只读取
+            [[self class] kb_markAppBootstrappedIfNeeded];
+            isAppBootstrapped = YES;
         }
-        [m applyLanguage:saved];
+        // 新安装判定（优先使用 App Group 标记）：卸载重装后 App Group 会被清理，但 Keychain 可能仍残留。
+        // 仅主 App 在检测到“本次安装从未启动过”时清理 Keychain，并写入系统择优结果，供扩展读取。
+        BOOL isFreshInstall = (!isAppExtension && !wasAppBootstrapped);
+        if (isFreshInstall) {
+            [[self class] kc_write:nil];
+            // 新安装：确保“未手动选择”状态（App Group 卸载重装会清理，这里再兜底一次）
+            [[self class] kb_setUserDidSelectLanguage:NO];
+        }
+        
+        // 兼容旧逻辑：仍保留标准 UserDefaults 的首次启动标记（仅主 App），但不再作为关键判定条件。
+        BOOL isFirstLaunch = (!isAppExtension) ? [[self class] kb_markLaunchedAndReturnIsFirstLaunch] : NO;
+
+        // 语言选择策略（满足产品规则）：
+        // 1) 用户在 App 内手动选过语言 -> 锁定（不跟随系统）；通过 Keychain 跨 Target 同步
+        // 2) 用户未手动选择过 -> 跟随系统当前语言（首选列表第一个），不读取/不写入 Keychain
+        BOOL userSelected = [[self class] kb_userDidSelectLanguage];
+        NSString *saved = nil;
+        if (userSelected) {
+            // 扩展在“主 App 尚未启动过”的场景下，忽略 Keychain（防止卸载重装遗留旧值在扩展先启动时生效）
+            if (!(isAppExtension && !isAppBootstrapped)) {
+                saved = (isFreshInstall ? nil : [[self class] kc_read]);
+            }
+        } else {
+            // 未手动选择：清理可能遗留的 Keychain（例如旧版本曾写入“系统默认”导致后续不再跟随系统）
+            if (!isAppExtension) {
+                NSString *legacy = [[self class] kc_read];
+                if (legacy.length > 0) {
+                    [[self class] kc_write:nil];
+                }
+            }
+        }
+#if DEBUG
+        NSLog(@"[KBLoc] init bundle=%@ isExt=%d appBoot=%d wasBoot=%d fresh=%d firstLaunch=%d userSelected=%d preferred=%@ keychainSaved=%@ supported=%@",
+              NSBundle.mainBundle.bundleIdentifier ?: @"",
+              isAppExtension, isAppBootstrapped, wasAppBootstrapped, isFreshInstall, isFirstLaunch,
+              userSelected,
+              [NSLocale preferredLanguages],
+              saved ?: @"(nil)",
+              m.supportedLanguageCodes ?: @[]);
+#endif
+        // 计算最终语言：优先手动选择；否则跟随系统当前语言（不在 5 种内则英文）
+        NSString *resolved = [m supportedLanguageCodeForCandidate:saved];
+        if (saved.length > 0 && resolved.length == 0) {
+            // 若保存了不支持的语言码（历史遗留），视为“未手动选择”，清理并回退系统
+            [[self class] kc_write:nil];
+            [[self class] kb_setUserDidSelectLanguage:NO];
+            saved = nil;
+            resolved = @"";
+        }
+        if (resolved.length == 0) {
+            resolved = [m bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
+        }
+        [m applyLanguage:resolved];
+#if DEBUG
+        NSLog(@"[KBLoc] resolved=%@ current=%@ bundle=%@",
+              resolved ?: @"",
+              m.currentLanguageCode ?: @"",
+              m.langBundle.bundlePath ?: @"");
+#endif
+
+        // 监听 Darwin 跨进程通知（语言变更），用于“App 内切语言 -> 立即刷新键盘”。
+        CFNotificationCenterAddObserver(CFNotificationCenterGetDarwinNotifyCenter(),
+                                        (__bridge const void *)(m),
+                                        KBLocDarwinCallback,
+                                        (__bridge CFStringRef)kKBDarwinLocalizationChanged,
+                                        NULL,
+                                        CFNotificationSuspensionBehaviorDeliverImmediately);
+
+        // 系统语言/地区变化：如果未手动锁定语言，则跟随系统刷新
+        [[NSNotificationCenter defaultCenter] addObserver:m
+                                                 selector:@selector(kb_onSystemLocaleMaybeChanged:)
+                                                     name:NSCurrentLocaleDidChangeNotification
+                                                   object:nil];
     });
     return m;
 }
@@ -90,15 +226,37 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
 
 - (void)setCurrentLanguageCode:(NSString *)code persist:(BOOL)persist {
     if (code.length == 0) return;                     // 忽略空值
-    if ([code isEqualToString:self.currentLanguageCode]) return; // 无变更
-    [self applyLanguage:code];
-    if (persist) { [[self class] kc_write:self.currentLanguageCode]; }    // 需同步到 App/扩展
+    // 仅允许切到“受支持语言”；不支持（如 zh-Hans）时按最佳匹配回退（默认 en）
+    NSString *resolved = [self supportedLanguageCodeForCandidate:code];
+    if (resolved.length == 0) {
+        resolved = [self bestSupportedLanguageForPreferred:@[code]] ?: (self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish);
+    }
+    if ([resolved isEqualToString:self.currentLanguageCode]) return; // 无变更
+    [self applyLanguage:resolved];
+    if (persist) {
+        [[self class] kb_setUserDidSelectLanguage:YES];
+        [[self class] kc_write:self.currentLanguageCode]; // 需同步到 App/扩展
+        // 通知对端进程刷新语言（特别是键盘扩展正在显示时）
+        CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
+                                             (__bridge CFStringRef)kKBDarwinLocalizationChanged,
+                                             NULL, NULL, true);
+    }
     [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
 }
 
 - (void)resetToSystemLanguage {
+    [[self class] kb_setUserDidSelectLanguage:NO];
+    [[self class] kc_write:nil];
     NSString *best = [self bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
-    [self setCurrentLanguageCode:best persist:NO];
+    if ([best isEqualToString:self.currentLanguageCode]) {
+        return;
+    }
+    [self applyLanguage:best];
+    // 通知对端进程刷新语言（特别是键盘扩展正在显示时）
+    CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
+                                         (__bridge CFStringRef)kKBDarwinLocalizationChanged,
+                                         NULL, NULL, true);
+    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
 }
 
 - (NSString *)localizedStringForKey:(NSString *)key {
@@ -116,15 +274,25 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
 
 - (NSString *)bestSupportedLanguageForPreferred:(NSArray<NSString *> *)preferred {
     if (self.supportedLanguageCodes.count == 0) return KBLanguageCodeEnglish;
+    // 需求：只使用“系统当前语言”（首选语言列表的第一个）。
+    // 若当前语言不在项目支持的 5 种语言内，则回退英文；不要从后续备选语言里再挑一个支持语言。
+    NSString *primary = preferred.firstObject ?: @"";
+    if (primary.length == 0) {
+        for (NSString *s in self.supportedLanguageCodes) {
+            if ([s.lowercaseString isEqualToString:@"en"]) { return s; }
+        }
+        return self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish;
+    }
+    NSArray<NSString *> *primaryOnly = @[ primary ];
     // 1) 完全匹配
-    for (NSString *p in preferred) {
+    for (NSString *p in primaryOnly) {
         NSString *pLC = p.lowercaseString;
         for (NSString *s in self.supportedLanguageCodes) {
             if ([pLC isEqualToString:s.lowercaseString]) { return s; }
         }
     }
     // 2) 前缀匹配：如 en-GB -> en, es-MX -> es
-    for (NSString *p in preferred) {
+    for (NSString *p in primaryOnly) {
         NSString *pLC = p.lowercaseString;
         for (NSString *s in self.supportedLanguageCodes) {
             NSString *sLC = s.lowercaseString;
@@ -138,7 +306,7 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
         }
     }
     // 2.5) 特殊处理葡语：pt-BR / pt-PT / pt -> pt-PT（若受支持）
-    for (NSString *p in preferred) {
+    for (NSString *p in primaryOnly) {
         NSString *pLC = p.lowercaseString;
         if ([pLC isEqualToString:@"pt"] || [pLC hasPrefix:@"pt-"] || [pLC hasPrefix:@"pt_"]) {
             for (NSString *s in self.supportedLanguageCodes) {
@@ -147,7 +315,7 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
         }
     }
     // 3) 特殊处理中文：将 zh-Hant/zh-TW/zh-HK 映射到 zh-Hant（若受支持）
-    for (NSString *p in preferred) {
+    for (NSString *p in primaryOnly) {
         NSString *pLC = p.lowercaseString;
         if ([pLC hasPrefix:@"zh-hant"] || [pLC hasPrefix:@"zh-tw"] || [pLC hasPrefix:@"zh-hk"]) {
             for (NSString *s in self.supportedLanguageCodes) {
@@ -155,7 +323,10 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
             }
         }
     }
-    // 4) 兜底：取第一个受支持语言
+    // 4) 兜底：若英文受支持则固定回退英文，否则取第一个
+    for (NSString *s in self.supportedLanguageCodes) {
+        if ([s.lowercaseString isEqualToString:@"en"]) { return s; }
+    }
     return self.supportedLanguageCodes.firstObject ?: KBLanguageCodeEnglish;
 }
 
@@ -165,7 +336,8 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
 
 #pragma mark - 内部实现
 
-- (void)applyLanguage:(NSString *)code {
+- (NSString *)normalizeLanguageCode:(NSString *)code {
+    if (code.length == 0) return @"";
     NSString *normalizedCode = code;
     NSString *lower = normalizedCode.lowercaseString;
     if ([lower isEqualToString:@"pt"] || [lower hasPrefix:@"pt-"] || [lower hasPrefix:@"pt_"]) {
@@ -175,6 +347,22 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
     if ([lower hasPrefix:@"zh-hant"] || [lower hasPrefix:@"zh_hant"] || [lower hasPrefix:@"zh-tw"] || [lower hasPrefix:@"zh_hk"]) {
         normalizedCode = KBLanguageCodeTraditionalChinese;
     }
+    return normalizedCode;
+}
+
+- (NSString *)supportedLanguageCodeForCandidate:(NSString *)code {
+    NSString *normalized = [self normalizeLanguageCode:code];
+    if (normalized.length == 0) return @"";
+    for (NSString *s in self.supportedLanguageCodes) {
+        if ([s.lowercaseString isEqualToString:normalized.lowercaseString]) {
+            return s; // 返回“工程内规范码”（保留大小写/连字符风格）
+        }
+    }
+    return @"";
+}
+
+- (void)applyLanguage:(NSString *)code {
+    NSString *normalizedCode = [self normalizeLanguageCode:code];
     _currentLanguageCode = [normalizedCode copy];
     // 基于当前 Target（App 或扩展）的主 bundle 加载 .lproj 资源
     NSString *path = [NSBundle.mainBundle pathForResource:normalizedCode ofType:@"lproj"];
@@ -194,6 +382,16 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
 
 #pragma mark - 钥匙串读写（App/扩展共享）
 
++ (BOOL)kb_markLaunchedAndReturnIsFirstLaunch {
+    // 注意：这里只能用主 App 自己的标准 UserDefaults。
+    // 不要用 App Group，否则键盘扩展可能会抢先写入“已启动”标记，导致主 App 无法在首次启动时清理历史 Keychain。
+    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
+    if ([ud boolForKey:kKBLocDidLaunchKey]) { return NO; }
+    [ud setBool:YES forKey:kKBLocDidLaunchKey];
+    [ud synchronize];
+    return YES;
+}
+
 + (BOOL)kc_write:(NSString *)lang {
     NSMutableDictionary *q = KBLocBaseKCQuery();
     SecItemDelete((__bridge CFDictionaryRef)q);
@@ -217,14 +415,60 @@ static inline NSMutableDictionary *KBLocBaseKCQuery(void) {
     return lang;
 }
 
-- (void)reloadFromSharedStorageIfNeeded {
-    NSString *saved = [[self class] kc_read];
-    if (saved.length == 0) return;
-    if ([saved isEqualToString:self.currentLanguageCode]) return;
+- (void)kb_onSystemLocaleMaybeChanged:(NSNotification *)note {
+    // 只有未手动选择语言时才需要跟随系统变化；手动选择情况下 reload 会优先读取保存值，不会被系统变化影响。
+    [self reloadFromSharedStorageIfNeeded];
+}
 
-    [self applyLanguage:saved];
-    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification
-                                                        object:nil];
+- (void)reloadFromSharedStorageIfNeeded {
+    BOOL userSelected = [[self class] kb_userDidSelectLanguage];
+    BOOL isAppExtension = [[self class] kb_isRunningInAppExtension];
+    BOOL isAppBootstrapped = [[self class] kb_isAppBootstrapped];
+
+    NSString *target = @"";
+    if (userSelected) {
+        // 扩展在主 App 未启动前：不读取 Keychain（可能遗留旧值），保持当前按系统择优的结果。
+        if (isAppExtension && !isAppBootstrapped) {
+#if DEBUG
+            NSLog(@"[KBLoc] reload skip (app not bootstrapped yet) bundle=%@ current=%@",
+                  NSBundle.mainBundle.bundleIdentifier ?: @"",
+                  self.currentLanguageCode ?: @"");
+#endif
+            return;
+        }
+        NSString *saved = [[self class] kc_read];
+        if (saved.length == 0) {
+            // 标记为手动选择但无保存值：降级为“跟随系统”
+            [[self class] kb_setUserDidSelectLanguage:NO];
+        } else {
+            NSString *resolved = [self supportedLanguageCodeForCandidate:saved];
+            if (resolved.length == 0) {
+                // 保存了不支持的语言码（历史遗留）：清理并降级为“跟随系统”
+                [[self class] kc_write:nil];
+                [[self class] kb_setUserDidSelectLanguage:NO];
+            } else {
+                target = resolved;
+            }
+        }
+    }
+
+    if (target.length == 0) {
+        // 未手动选择：始终按系统当前语言（首选列表第一个）择优
+        target = [self bestSupportedLanguageForPreferred:[NSLocale preferredLanguages]] ?: KBLanguageCodeEnglish;
+    }
+
+    if ([target isEqualToString:self.currentLanguageCode]) {
+        return;
+    }
+
+    [self applyLanguage:target];
+    // 系统跟随模式：主 App 语言变化时需要通知键盘扩展即时刷新（避免键盘仍停留旧语言）。
+    if (!userSelected && !isAppExtension) {
+        CFNotificationCenterPostNotification(CFNotificationCenterGetDarwinNotifyCenter(),
+                                             (__bridge CFStringRef)kKBDarwinLocalizationChanged,
+                                             NULL, NULL, true);
+    }
+    [[NSNotificationCenter defaultCenter] postNotificationName:KBLocalizationDidChangeNotification object:nil];
 }
 
 @end
diff --git a/Shared/KBSkinInstallBridge.m b/Shared/KBSkinInstallBridge.m
index 780ed0b..4f10f28 100644
--- a/Shared/KBSkinInstallBridge.m
+++ b/Shared/KBSkinInstallBridge.m
@@ -1021,6 +1021,18 @@ static NSString * const kKBSkinMetadataThemeKey        = @"theme_json";
               targetSkinId, themeOK, (unsigned long)iconPathMap.count);
         return themeOK;
     }
+
+    // 目标默认皮肤不存在：如果当前仍是“默认类皮肤”，为避免 key_icons 仍是旧语言导致看起来“还是繁体”，回退到无图标的默认主题。
+    // 等主 App 后续安装/应用对应语言的默认皮肤后，会通过 KBSkinManager 的 Darwin 通知同步到扩展。
+    if (!hasTargetSkin && isDefaultLike &&
+        currentSkinId.length > 0 &&
+        ![currentSkinId isEqualToString:@"default"] &&
+        [currentSkinId hasPrefix:@"bundle_skin_default_"] &&
+        ![currentSkinId isEqualToString:targetSkinId]) {
+        NSLog(@"[SkinBridge] reloadCurrentSkinIconMap: missing target skin, fallback to default theme (clear old icon map)");
+        [[KBSkinManager shared] resetToDefault];
+        return YES;
+    }
     
     // 如果目标皮肤不存在，尝试更新当前皮肤的图标映射
     if (currentSkinId.length == 0 || [currentSkinId isEqualToString:@"default"]) {
diff --git a/keyBoard/AppDelegate.m b/keyBoard/AppDelegate.m
index 418e0c0..5201f08 100644
--- a/keyBoard/AppDelegate.m
+++ b/keyBoard/AppDelegate.m
@@ -25,8 +25,11 @@
 #import "KBUserSessionManager.h"
 #import "KBLoginVC.h"
 #import "KBConfig.h"
+#import "KBLocalizationManager.h"
 #import "KBSkinInstallBridge.h"
+#import "KBSkinManager.h"
 #import "KBAppUpdateView.h"
+#import "KBInputProfileManager.h"
 
 static NSTimeInterval const kKBSubscriptionPrefillTTL = 10 * 60.0;
 
@@ -46,6 +49,10 @@ static NSTimeInterval const kKBSubscriptionPrefillTTL = 10 * 60.0;
 - (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
     /// 1：配置国际化（统一使用集中管理的语言列表）
     [KBLocalizationManager shared].supportedLanguageCodes = KBDefaultSupportedLanguageCodes();
+    /// 1.1：首次启动为键盘写入默认输入配置（语言/布局/profile），保证“App 语言=键盘语言”
+    [self kb_bootstrapDefaultKeyboardProfileIfNeeded];
+    /// 1.2：未手动选择键盘输入配置时，让键盘配置随 App 语言变化
+    [self kb_syncKeyboardProfileToCurrentAppLanguageIfNeeded];
     /// 2 : 处理token问题（包括卸载重装场景下的 token 清理）
     [[KBUserSessionManager shared] bootstrapIfNeeded];
 
@@ -73,6 +80,12 @@ static NSTimeInterval const kKBSubscriptionPrefillTTL = 10 * 60.0;
     
     // 安装默认皮肤（首次安装时）
     [self kb_installDefaultSkinIfNeeded];
+
+    // App 语言变化（系统跟随或手动切换）时，同步键盘配置并让键盘即时刷新
+    [[NSNotificationCenter defaultCenter] addObserver:self
+                                             selector:@selector(kb_onLocalizationChanged:)
+                                                 name:KBLocalizationDidChangeNotification
+                                               object:nil];
     
     [self kb_requestAppUpdateAndPresentIfNeeded];
     
@@ -87,6 +100,119 @@ static NSTimeInterval const kKBSubscriptionPrefillTTL = 10 * 60.0;
     return YES;
 }
 
+- (NSString *)kb_defaultKeyboardLanguageCodeForAppLanguageCode:(NSString *)appLanguageCode {
+    NSString *lc = appLanguageCode.lowercaseString ?: @"";
+    if ([lc hasPrefix:@"es"]) { return @"es"; }
+    if ([lc hasPrefix:@"pt"]) { return @"pt"; }
+    if ([lc hasPrefix:@"id"]) { return @"id"; }
+    if ([lc hasPrefix:@"zh-hant"]) { return @"zh-Hant-Pinyin"; }
+    return @"en";
+}
+
+- (void)kb_bootstrapDefaultKeyboardProfileIfNeeded {
+    NSUserDefaults *shared = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
+    NSString *savedProfileId = [shared stringForKey:AppGroup_SelectedKeyboardProfileId];
+    if (savedProfileId.length > 0) {
+        return;
+    }
+    
+    NSString *appLanguageCode = [KBLocalizationManager shared].currentLanguageCode ?: KBLanguageCodeEnglish;
+    NSString *kbLanguageCode = [self kb_defaultKeyboardLanguageCodeForAppLanguageCode:appLanguageCode];
+    KBInputProfile *profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:kbLanguageCode];
+    if (!profile) {
+        profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:@"en"];
+    }
+    KBInputProfileLayout *layout = profile.layouts.firstObject;
+    if (!layout) {
+        return;
+    }
+    
+    [shared setObject:(profile.code ?: @"en") forKey:AppGroup_SelectedKeyboardLanguageCode];
+    [shared setObject:(layout.variant ?: @"qwerty") forKey:AppGroup_SelectedKeyboardLayoutVariant];
+    [shared setObject:(layout.profileId ?: @"en_US_qwerty") forKey:AppGroup_SelectedKeyboardProfileId];
+    [shared synchronize];
+    
+    NSLog(@"[AppDelegate] Bootstrap keyboard profile: appLang=%@ kbLang=%@ profileId=%@ variant=%@",
+          appLanguageCode, profile.code, layout.profileId, layout.variant);
+}
+
+- (void)kb_syncKeyboardProfileToCurrentAppLanguageIfNeeded {
+    NSUserDefaults *shared = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
+    if ([shared boolForKey:AppGroup_DidUserSelectKeyboardProfile]) {
+        return;
+    }
+    NSString *appLanguageCode = [KBLocalizationManager shared].currentLanguageCode ?: KBLanguageCodeEnglish;
+    NSString *kbLanguageCode = [self kb_defaultKeyboardLanguageCodeForAppLanguageCode:appLanguageCode];
+
+    KBInputProfile *profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:kbLanguageCode];
+    if (!profile) {
+        profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:@"en"];
+    }
+    KBInputProfileLayout *layout = profile.layouts.firstObject;
+    if (!layout) {
+        return;
+    }
+
+    NSString *curProfileId = [shared stringForKey:AppGroup_SelectedKeyboardProfileId] ?: @"";
+    NSString *curLang = [shared stringForKey:AppGroup_SelectedKeyboardLanguageCode] ?: @"";
+    NSString *curVariant = [shared stringForKey:AppGroup_SelectedKeyboardLayoutVariant] ?: @"";
+    if ([curProfileId isEqualToString:layout.profileId ?: @""] &&
+        [curLang isEqualToString:profile.code ?: @""] &&
+        [curVariant isEqualToString:layout.variant ?: @""]) {
+        return;
+    }
+
+    [shared setObject:(profile.code ?: @"en") forKey:AppGroup_SelectedKeyboardLanguageCode];
+    [shared setObject:(layout.variant ?: @"qwerty") forKey:AppGroup_SelectedKeyboardLayoutVariant];
+    [shared setObject:(layout.profileId ?: @"en_US_qwerty") forKey:AppGroup_SelectedKeyboardProfileId];
+    [shared synchronize];
+
+    NSLog(@"[AppDelegate] Sync keyboard profile to appLang=%@ kbLang=%@ profileId=%@ variant=%@",
+          appLanguageCode, profile.code, layout.profileId, layout.variant);
+
+    // 同步完键盘语言后，如当前是默认皮肤，则让皮肤也跟随（避免 key_icons 仍是旧语言导致看起来“还是繁体”）
+    [self kb_applyDefaultSkinForKeyboardLanguageIfNeeded:profile.code ?: @"en"];
+}
+
+- (void)kb_onLocalizationChanged:(NSNotification *)note {
+    [self kb_syncKeyboardProfileToCurrentAppLanguageIfNeeded];
+}
+
+- (void)kb_applyDefaultSkinForKeyboardLanguageIfNeeded:(NSString *)languageCode {
+    NSString *lc = languageCode.length > 0 ? languageCode : @"en";
+    NSString *targetSkinId = [NSString stringWithFormat:@"bundle_skin_default_%@", lc];
+    NSString *currentSkinId = [KBSkinManager shared].current.skinId ?: @"";
+    BOOL isDefaultLike = (currentSkinId.length == 0 ||
+                          [currentSkinId isEqualToString:@"default"] ||
+                          [currentSkinId hasPrefix:@"bundle_skin_default_"]);
+    if (!isDefaultLike) {
+        return;
+    }
+    if ([currentSkinId isEqualToString:targetSkinId] && [KBSkinManager kb_hasAssetsForSkinId:targetSkinId]) {
+        return;
+    }
+
+    KBInputProfile *profile = [[KBInputProfileManager sharedManager] profileForLanguageCode:lc];
+    NSString *zipName = profile.defaultSkinZip.length > 0 ? profile.defaultSkinZip : @"normal_them.zip";
+    NSDictionary<NSString *, NSString *> *iconShortNames = [KBSkinInstallBridge iconShortNamesForLanguageCode:lc];
+
+    NSLog(@"[AppDelegate] Applying default skin for keyboard language=%@ currentSkin=%@ targetSkin=%@ zip=%@",
+          lc, currentSkinId, targetSkinId, zipName);
+
+    [KBSkinInstallBridge publishBundleSkinRequestWithId:targetSkinId
+                                                  name:targetSkinId
+                                               zipName:zipName
+                                        iconShortNames:iconShortNames];
+    [KBSkinInstallBridge consumePendingRequestFromBundle:[NSBundle mainBundle]
+                                              completion:^(BOOL success, NSError * _Nullable error) {
+        if (!success) {
+            NSLog(@"[AppDelegate] Apply default skin failed: %@", error);
+        } else {
+            NSLog(@"[AppDelegate] Apply default skin success: %@", targetSkinId);
+        }
+    }];
+}
+
 - (void)kb_requestAppUpdateAndPresentIfNeeded {
     __weak typeof(self) weakSelf = self;
     [[KBLoginVM shared] checkAppUpdateWithCompletion:^(KBAppUpdateInfo * _Nullable info, NSError * _Nullable error) {
@@ -545,36 +671,14 @@ static NSTimeInterval const kKBSubscriptionPrefillTTL = 10 * 60.0;
 }
 
 - (void)kb_installDefaultSkinIfNeeded {
-    static NSString *const kKBDefaultSkinInstalledKey = @"KBDefaultSkinInstalled";
-    NSUserDefaults *ud = [NSUserDefaults standardUserDefaults];
-    
-    if ([ud boolForKey:kKBDefaultSkinInstalledKey]) {
-        NSLog(@"[AppDelegate] Default skin already installed, skip");
-        return;
+    NSLog(@"[AppDelegate] Installing/applying default skin if needed...");
+    NSUserDefaults *shared = [[NSUserDefaults alloc] initWithSuiteName:AppGroup];
+    NSString *languageCode = [shared stringForKey:AppGroup_SelectedKeyboardLanguageCode];
+    if (languageCode.length == 0) {
+        NSString *appLanguageCode = [KBLocalizationManager shared].currentLanguageCode ?: KBLanguageCodeEnglish;
+        languageCode = [self kb_defaultKeyboardLanguageCodeForAppLanguageCode:appLanguageCode];
     }
-    
-    NSLog(@"[AppDelegate] Installing default skin for first launch...");
-    
-    NSString *skinId = @"bundle_skin_default_en";
-    NSString *zipName = @"normal_them.zip";
-    
-    NSDictionary<NSString *, NSString *> *iconShortNames = [KBSkinInstallBridge iconShortNamesForLanguageCode:@"en"];
-    
-    [KBSkinInstallBridge publishBundleSkinRequestWithId:skinId
-                                                  name:skinId
-                                               zipName:zipName
-                                        iconShortNames:iconShortNames];
-    
-    [KBSkinInstallBridge consumePendingRequestFromBundle:[NSBundle mainBundle]
-                                              completion:^(BOOL success, NSError * _Nullable error) {
-        if (success) {
-            NSLog(@"[AppDelegate] Default skin installed successfully");
-            [ud setBool:YES forKey:kKBDefaultSkinInstalledKey];
-            [ud synchronize];
-        } else {
-            NSLog(@"[AppDelegate] Default skin install failed: %@", error);
-        }
-    }];
+    [self kb_applyDefaultSkinForKeyboardLanguageIfNeeded:languageCode ?: @"en"];
 }
 
 @end
diff --git a/keyBoard/Class/Me/VC/KBPersonInfoVC.m b/keyBoard/Class/Me/VC/KBPersonInfoVC.m
index 58cb61f..45d8e73 100644
--- a/keyBoard/Class/Me/VC/KBPersonInfoVC.m
+++ b/keyBoard/Class/Me/VC/KBPersonInfoVC.m
@@ -630,6 +630,7 @@ typedef void(^KBInputProfileSelectHandler)(NSString *languageCode, NSString *lay
     [shared setObject:languageCode forKey:AppGroup_SelectedKeyboardLanguageCode];
     [shared setObject:layoutVariant forKey:AppGroup_SelectedKeyboardLayoutVariant];
     [shared setObject:profileId forKey:AppGroup_SelectedKeyboardProfileId];
+    [shared setBool:YES forKey:AppGroup_DidUserSelectKeyboardProfile];
     [shared synchronize];
 
     [[KBLocalizationManager shared] setCurrentLanguageCode:languageCode persist:YES];