postcast-tool/components/ThemeToggle.js

'use client';
import { useEffect, useState } from 'react';
import { Sun, Moon } from 'lucide-react';

export default function ThemeToggle() {
  const [theme, setTheme] = useState(null);

  useEffect(() => {
    const saved = typeof window !== 'undefined' && localStorage.getItem('zp_theme');
    const current = saved || 'light';
    setTheme(current);
    document.documentElement.setAttribute('data-theme', current);
  }, []);

  function toggle() {
    const next = theme === 'dark' ? 'light' : 'dark';
    setTheme(next);
    document.documentElement.setAttribute('data-theme', next);
    localStorage.setItem('zp_theme', next);
  }

  // На SSR не рендерим (избегаем mismatch)
  if (!theme) return <div className="w-9 h-9" />;

  return (
    <button
      onClick={toggle}
      title={theme === 'dark' ? 'Светлая тема' : 'Тёмная тема'}
      className="w-9 h-9 inline-flex items-center justify-center rounded-lg hover:bg-surface2 transition-colors"
    >
      {theme === 'dark' ? <Sun className="w-4 h-4" /> : <Moon className="w-4 h-4" />}
    </button>
  );
}