(() => {
  const body = document.body;

  // Mobiles Menü
  const burger = document.querySelector('.burger');
  if (burger) {
    burger.addEventListener('click', () => {
      const open = body.classList.toggle('menu-open');
      burger.setAttribute('aria-expanded', open);
    });
    document.querySelectorAll('.nav a').forEach(a =>
      a.addEventListener('click', () => {
        body.classList.remove('menu-open');
        burger.setAttribute('aria-expanded', 'false');
      })
    );
  }

  // Startseite: Header einblenden, sobald der Hero verlassen wird
  const hero = document.querySelector('.hero');
  if (body.classList.contains('is-home') && hero) {
    new IntersectionObserver(([e]) => body.classList.toggle('scrolled', !e.isIntersecting), {
      rootMargin: '-120px 0px 0px 0px'
    }).observe(hero);
  }

  // Elemente beim Scrollen einblenden
  const items = document.querySelectorAll('.reveal');
  if ('IntersectionObserver' in window) {
    const io = new IntersectionObserver(entries => {
      entries.forEach(e => {
        if (e.isIntersecting) {
          e.target.classList.add('in');
          io.unobserve(e.target);
        }
      });
    }, { threshold: 0.12, rootMargin: '0px 0px -40px 0px' });
    items.forEach(el => io.observe(el));
  } else {
    items.forEach(el => el.classList.add('in'));
  }
})();