(() => {
  const $ = (s, root = document) => root.querySelector(s);
  const $$ = (s, root = document) => [...root.querySelectorAll(s)];
  const header = $('#siteHeader');
  const progress = $('#scrollProgress');
  const bottomCta = $('#bottomCta');
  const toTop = $('#toTop');
  const menu = $('#mobileMenu');
  const menuToggle = $('#menuToggle');
  const accessPanel = $('#accessPanel');
  const root = document.documentElement;

  const setLock = (locked) => document.body.classList.toggle('menu-lock', locked);

  function onScroll(){
    const y = window.scrollY;
    const h = Math.max(1, document.documentElement.scrollHeight - window.innerHeight);
    header?.classList.toggle('scrolled', y > 18);
    if(progress) progress.style.width = `${Math.min(100, (y / h) * 100)}%`;

    const ctaSection = $('#cta');
    const footer = $('#contact');
    const ctaTop = ctaSection ? ctaSection.getBoundingClientRect().top + y : Infinity;
    const footerTop = footer ? footer.getBoundingClientRect().top + y : Infinity;
    const shouldShow = y > window.innerHeight * .78 && y + window.innerHeight < Math.min(ctaTop + 120, footerTop);
    bottomCta?.classList.toggle('show', shouldShow);
    toTop?.classList.toggle('show', y > 650);
  }
  addEventListener('scroll', onScroll, {passive:true});
  addEventListener('resize', onScroll, {passive:true});
  onScroll();

  if('IntersectionObserver' in window){
    const revealObserver = new IntersectionObserver(entries => {
      entries.forEach(entry => {
        if(entry.isIntersecting){
          entry.target.classList.add('in');
          revealObserver.unobserve(entry.target);
        }
      });
    }, {threshold:.12, rootMargin:'0px 0px -30px 0px'});
    $$('.reveal').forEach(el => revealObserver.observe(el));

    const sections = $$('main section[id]');
    const navLinks = $$('.nav-links a');
    const activeObserver = new IntersectionObserver(entries => {
      entries.forEach(entry => {
        if(entry.isIntersecting){
          navLinks.forEach(a => a.classList.toggle('active', a.getAttribute('href') === `#${entry.target.id}`));
        }
      });
    }, {rootMargin:'-40% 0px -50% 0px'});
    sections.forEach(section => activeObserver.observe(section));
  } else {
    $$('.reveal').forEach(el => el.classList.add('in'));
  }

  function openMenu(){
    menu?.classList.add('open');
    menu?.setAttribute('aria-hidden','false');
    menuToggle?.setAttribute('aria-expanded','true');
    setLock(true);
  }
  function closeMenu(){
    menu?.classList.remove('open');
    menu?.setAttribute('aria-hidden','true');
    menuToggle?.setAttribute('aria-expanded','false');
    if(!accessPanel?.classList.contains('open')) setLock(false);
  }
  menuToggle?.addEventListener('click', openMenu);
  $('#closeMenu')?.addEventListener('click', closeMenu);
  menu?.addEventListener('click', e => { if(e.target === menu || e.target.closest('a')) closeMenu(); });

  function openAccess(){
    accessPanel?.classList.add('open');
    accessPanel?.setAttribute('aria-hidden','false');
    setLock(true);
  }
  function closeAccess(){
    accessPanel?.classList.remove('open');
    accessPanel?.setAttribute('aria-hidden','true');
    if(!menu?.classList.contains('open')) setLock(false);
  }
  $$('.access-open').forEach(btn => btn.addEventListener('click', openAccess));
  $('#closeAccess')?.addEventListener('click', closeAccess);
  accessPanel?.addEventListener('click', e => { if(e.target === accessPanel) closeAccess(); });

  let saved = {};
  try { saved = JSON.parse(localStorage.getItem('psrcAccess') || '{}'); } catch(_) {}
  if(saved.scale) root.style.setProperty('--font-scale', saved.scale);
  if(saved.contrast) document.body.classList.add('high-contrast');
  if(saved.motion) document.body.classList.add('reduce-motion');

  function saveAccess(){
    localStorage.setItem('psrcAccess', JSON.stringify({
      scale: getComputedStyle(root).getPropertyValue('--font-scale').trim() || '1',
      contrast: document.body.classList.contains('high-contrast'),
      motion: document.body.classList.contains('reduce-motion')
    }));
  }

  accessPanel?.addEventListener('click', e => {
    const action = e.target.dataset.access;
    if(!action) return;
    const scale = parseFloat(getComputedStyle(root).getPropertyValue('--font-scale')) || 1;
    if(action === 'fontPlus') root.style.setProperty('--font-scale', Math.min(1.18, scale + .06));
    if(action === 'fontMinus') root.style.setProperty('--font-scale', Math.max(.92, scale - .06));
    if(action === 'contrast') document.body.classList.toggle('high-contrast');
    if(action === 'motion') document.body.classList.toggle('reduce-motion');
    if(action === 'reset'){
      root.style.setProperty('--font-scale', 1);
      document.body.classList.remove('high-contrast','reduce-motion');
      localStorage.removeItem('psrcAccess');
      return;
    }
    saveAccess();
  });

  toTop?.addEventListener('click', () => window.scrollTo({top:0, behavior: document.body.classList.contains('reduce-motion') ? 'auto' : 'smooth'}));
  addEventListener('keydown', e => { if(e.key === 'Escape'){ closeMenu(); closeAccess(); } });
})();