fix: theme toggle error

src/layouts/Head.astro

@@ -95,19 +95,32 @@ const { cdn, commentURL = '', imageHostURL = '', customGoogleAnalyticsURL = '',
 
 <!-- Theme Toggle -->
 <script is:inline define:vars={{ defaultMode: themeConfig.color.mode }}>
-function getTheme() {
-  const storedTheme = localStorage.getItem('theme')
-  if (storedTheme)
-    return storedTheme
-  const systemTheme = window.matchMedia('(prefers-color-scheme: dark)').matches
-  return systemTheme ? 'dark' : defaultMode
-}
-function updateTheme() {
-  const theme = localStorage.getItem('theme') || getTheme()
+function initTheme() {
+  const theme = (() => {
+    // 1. 检查 localStorage
+    if (typeof localStorage !== 'undefined' && localStorage.getItem('theme')) {
+      return localStorage.getItem('theme')
+    }
+    // 2. 检查系统主题
+    if (window.matchMedia('(prefers-color-scheme: dark)').matches) {
+      return 'dark'
+    }
+    // 3. 使用默认主题
+    return defaultMode
+  })()
+
   document.documentElement.classList.toggle('dark', theme === 'dark')
 }
-updateTheme()
-document.addEventListener('astro:after-swap', updateTheme)
+
+// 立即执行初始化
+initTheme()
+
+// 监听系统主题变化
+window.matchMedia('(prefers-color-scheme: dark)').addEventListener('change', (e) => {
+  if (!localStorage.getItem('theme')) { // 只在用户未手动设置主题时响应
+    document.documentElement.classList.toggle('dark', e.matches)
+  }
+})
 </script>
 
 <!-- Google Analytics -->