diff --git a/docs/.vitepress/components/ParallaxCoverChristmas20251224.vue b/docs/.vitepress/components/ParallaxCoverChristmas20251224.vue
index e16a73970..ec0d5f26f 100644
--- a/docs/.vitepress/components/ParallaxCoverChristmas20251224.vue
+++ b/docs/.vitepress/components/ParallaxCoverChristmas20251224.vue
@@ -84,7 +84,7 @@ const maskImageURL = `url(${homeCover})`
       'md:w-[150%] md:translate-y-[40%] md:rotate-[0deg] md:top-8dvh',
       'lg:w-[95%] lg:translate-y-[-20%] lg:translate-x-[-50%] lg:rotate-[0deg] lg:scale-95 lg:top-32dvh',
       'xl:translate-y-[-50%] xl:translate-x-[-50%] xl:scale-80 xl:top-18dvh',
-      '2xl:w-[100%] 2xl:translate-y-[-20%] 2xl:translate-x-[-50%] 2xl:rotate-[0deg] 2xl:top-16dvh',
+      '2xl:w-[100%] 2xl:translate-y-[-20%] 2xl:translate-x-[-50%] 2xl:rotate-[0deg] 2xl:scale-60 2xl:top-12dvh',
     ]"
   >
     <img ref="surface" :src="homeCover" alt="Project AIRI Cover Image" class="w-full object-cover">
diff --git a/docs/.vitepress/theme/index.ts b/docs/.vitepress/theme/index.ts
index e74f215e8..f3dd8f0e2 100644
--- a/docs/.vitepress/theme/index.ts
+++ b/docs/.vitepress/theme/index.ts
@@ -23,14 +23,14 @@ import '@fontsource-variable/comfortaa'
 
 export default {
   Layout,
-  enhanceApp({ app }) {
+  enhanceApp({ app, siteData }) {
     if (!import.meta.env.SSR) {
       import('../modules/posthog')
     }
 
     const i18n = createI18n({
       legacy: false,
-      locale: 'en',
+      locale: siteData.value.lang || 'en',
       fallbackLocale: 'en',
       messages,
     })
diff --git a/docs/content/ja/docs/overview/index.md b/docs/content/ja/docs/overview/index.md
index fbf93ce5e..4443990a9 100644
--- a/docs/content/ja/docs/overview/index.md
+++ b/docs/content/ja/docs/overview/index.md
@@ -1,3 +1,4 @@
+---
 title: これはどんなプロジェクト？
 description: Project AIRI のユーザーインターフェースを知る
 ---
@@ -70,7 +71,7 @@ Web 版は手軽にアクセスでき、モバイルからでも利用できま
       使い方を見る
     </div>
   </a>
-  <a href="../../../en/docs/guide/web/" w-full flex items-center gap-2 border="2 solid gray-500/10" rounded-lg px-4 py-2>
+  <a href="../../../en/docs/overview/guide/web/" w-full flex items-center gap-2 border="2 solid gray-500/10" rounded-lg px-4 py-2>
     <div w-full flex items-center gap-2>
       <div flex items-center gap-2 text-2xl>
       <div i-lucide:app-window />
diff --git a/packages/i18n/src/locales/index.ts b/packages/i18n/src/locales/index.ts
index 784fd27b0..7213a9edc 100644
--- a/packages/i18n/src/locales/index.ts
+++ b/packages/i18n/src/locales/index.ts
@@ -1,6 +1,8 @@
 import en from './en'
 import es from './es'
 import fr from './fr'
+import ja from './ja'
+import ko from './ko'
 import ru from './ru'
 import vi from './vi'
 import zhHans from './zh-Hans'
@@ -10,6 +12,8 @@ export default {
   en,
   es,
   fr,
+  ko,
+  ja,
   ru,
   vi,
   'zh-Hans': zhHans,
diff --git a/packages/i18n/src/locales/ja/docs/index.ts b/packages/i18n/src/locales/ja/docs/index.ts
new file mode 100644
index 000000000..73db92d8e
--- /dev/null
+++ b/packages/i18n/src/locales/ja/docs/index.ts
@@ -0,0 +1,7 @@
+import theme from './theme.yaml'
+import versions from './versions.yaml'
+
+export default {
+  theme,
+  versions,
+}
diff --git a/packages/i18n/src/locales/ja/index.ts b/packages/i18n/src/locales/ja/index.ts
new file mode 100644
index 000000000..298366a0d
--- /dev/null
+++ b/packages/i18n/src/locales/ja/index.ts
@@ -0,0 +1,13 @@
+import base from './base.yaml'
+import docs from './docs'
+import settings from './settings.yaml'
+import stage from './stage.yaml'
+import tamagotchi from './tamagotchi'
+
+export default {
+  base,
+  docs,
+  settings,
+  stage,
+  tamagotchi,
+}
diff --git a/packages/i18n/src/locales/ja/tamagotchi/index.ts b/packages/i18n/src/locales/ja/tamagotchi/index.ts
new file mode 100644
index 000000000..e123ae5b4
--- /dev/null
+++ b/packages/i18n/src/locales/ja/tamagotchi/index.ts
@@ -0,0 +1,7 @@
+import settings from './settings.yaml'
+import stage from './stage.yaml'
+
+export default {
+  stage,
+  settings,
+}
diff --git a/packages/i18n/src/locales/ko/docs/index.ts b/packages/i18n/src/locales/ko/docs/index.ts
new file mode 100644
index 000000000..73db92d8e
--- /dev/null
+++ b/packages/i18n/src/locales/ko/docs/index.ts
@@ -0,0 +1,7 @@
+import theme from './theme.yaml'
+import versions from './versions.yaml'
+
+export default {
+  theme,
+  versions,
+}
diff --git a/packages/i18n/src/locales/ko/index.ts b/packages/i18n/src/locales/ko/index.ts
new file mode 100644
index 000000000..298366a0d
--- /dev/null
+++ b/packages/i18n/src/locales/ko/index.ts
@@ -0,0 +1,13 @@
+import base from './base.yaml'
+import docs from './docs'
+import settings from './settings.yaml'
+import stage from './stage.yaml'
+import tamagotchi from './tamagotchi'
+
+export default {
+  base,
+  docs,
+  settings,
+  stage,
+  tamagotchi,
+}
diff --git a/packages/i18n/src/locales/ko/tamagotchi/index.ts b/packages/i18n/src/locales/ko/tamagotchi/index.ts
new file mode 100644
index 000000000..e123ae5b4
--- /dev/null
+++ b/packages/i18n/src/locales/ko/tamagotchi/index.ts
@@ -0,0 +1,7 @@
+import settings from './settings.yaml'
+import stage from './stage.yaml'
+
+export default {
+  stage,
+  settings,
+}