feat(public): add setting dark or light mode

app/components/layout/Header.vue

@@ -1,4 +1,6 @@
 <script setup lang="ts">
+import ThemeToggle from "./ThemeToggle.vue"
+
 const route = useRoute()
 
 function setLinks() {
@@ -48,9 +50,10 @@ watch(
       <Separator orientation="vertical" class="h-4" />
       <!-- <BaseBreadcrumbCustom :links="links" /> -->
     </div>
-    <div class="ml-auto">
-      <slot />
-    </div>
+     <div class="ml-auto flex items-center gap-2">
+       <slot />
+       <ThemeToggle />
+     </div>
   </header>
 </template>
 

app/components/layout/ThemeToggle.vue

@@ -0,0 +1,15 @@
+<script setup lang="ts">
+import { useTheme } from '~/composables/useTheme'
+const { theme, toggleTheme } = useTheme()
+</script>
+
+<template>
+  <button
+    @click="toggleTheme"
+    class="ml-2 flex items-center rounded border px-2 py-1"
+    :title="theme === 'dark' ? 'Switch to light mode' : 'Switch to dark mode'"
+  >
+    <span v-if="theme === 'dark'"><Icon name="i-lucide-moon" class="h-4 w-4" /></span>
+    <span v-else><Icon name="i-lucide-sun" class="h-4 w-4" /></span>
+  </button>
+</template>

app/composables/useTheme.ts

@@ -0,0 +1,31 @@
+import { ref, watchEffect } from 'vue'
+
+const THEME_KEY = 'theme-mode'
+
+export function useTheme() {
+  const theme = ref<'light' | 'dark'>(getInitialTheme())
+
+  function getInitialTheme() {
+    if (typeof window === 'undefined') return 'light'
+    const persisted = localStorage.getItem(THEME_KEY)
+    if (persisted === 'dark' || persisted === 'light') return persisted
+    // fallback: system preference
+    return window.matchMedia('(prefers-color-scheme: dark)').matches ? 'dark' : 'light'
+  }
+
+  function setTheme(newTheme: 'light' | 'dark') {
+    theme.value = newTheme
+    localStorage.setItem(THEME_KEY, newTheme)
+    document.documentElement.classList.toggle('dark', newTheme === 'dark')
+  }
+
+  function toggleTheme() {
+    setTheme(theme.value === 'dark' ? 'light' : 'dark')
+  }
+
+  watchEffect(() => {
+    setTheme(theme.value)
+  })
+
+  return { theme, toggleTheme }
+}