mobile nav implemented

dark mode need rifinements

frontend/src/components/layout/ThemeToggle.tsx

@@ -0,0 +1,38 @@
+import { useState, useEffect } from 'react';
+import { Button } from '@/components/ui/button';
+import { Sun, Moon } from 'lucide-react';
+import { getInitialTheme, toggleTheme, watchSystemTheme } from '@/lib/theme';
+
+export function ThemeToggle() {
+  const [theme, setTheme] = useState<'light' | 'dark'>(getInitialTheme);
+
+  useEffect(() => {
+    // Watch for system theme changes
+    const cleanup = watchSystemTheme((newTheme) => {
+      setTheme(newTheme);
+    });
+    
+    return cleanup;
+  }, []);
+
+  const handleToggle = () => {
+    const newTheme = toggleTheme();
+    setTheme(newTheme);
+  };
+
+  return (
+    <Button
+      variant="ghost"
+      size="icon"
+      onClick={handleToggle}
+      className="h-9 w-9"
+      aria-label={`Switch to ${theme === 'light' ? 'dark' : 'light'} mode`}
+    >
+      {theme === 'light' ? (
+        <Moon className="h-4 w-4" />
+      ) : (
+        <Sun className="h-4 w-4" />
+      )}
+    </Button>
+  );
+}