fix: theme toggle error

src/components/ThemeToggle.astro

@@ -20,15 +20,18 @@
     document.startViewTransition(switchTheme)
   }
 
-  // Synchronize theme status
+  // Sync theme state
   function syncTheme() {
     const theme = localStorage.getItem('theme')
     document.documentElement.classList.toggle('dark', theme === 'dark')
     themeToggle.setAttribute('aria-pressed', String(theme === 'dark'))
   }
 
+  // Event listeners
   themeToggle.addEventListener('click', toggleTheme)
   document.addEventListener('astro:after-swap', syncTheme)
+  window.addEventListener('popstate', syncTheme)
+  document.addEventListener('DOMContentLoaded', syncTheme)
 </script>
 
 <button