import { useState, useEffect } from 'react'; interface TopNavProps { onLogout?: () => void; } export function TopNav({ onLogout }: TopNavProps) { const [currentTime, setCurrentTime] = useState(''); useEffect(() => { const update = () => setCurrentTime(new Date().toLocaleString('zh-CN')); update(); const timer = setInterval(update, 1000); return () => clearInterval(timer); }, []); return ( ); }