Function applyDarkMode

public/js/main.js:854–903

({ fromSystemChange = false } = {})

// -------- DARK MODE (persist + system fallback + a11y labels) --------
function applyDarkMode({ fromSystemChange = false } = {}) {
  let stored = null;
  try { stored = localStorage.getItem('darkMode'); } catch (e) { }

  let isDark = (stored === null)
    ? (window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches)
    : (stored === '1' || stored === 'true');

  const root = document.documentElement;
  const body = document.body;

  [root, body].forEach(el => {
    if (!el) return;
    el.classList.toggle('dark-mode', isDark);
    el.setAttribute('data-theme', isDark ? 'dark' : 'light');
  });

  // keep UA chrome & bg consistent post-toggle
  const customBg = resolveAppBackground(isDark);
  const bg = customBg || (isDark ? '#121212' : '#ffffff');
  const isLoginView = body && body.classList.contains('fr-login-view');
  if (isLoginView) {
    root.style.background = '';
    root.style.backgroundColor = '';
    if (body) {
      body.style.background = '';
      body.style.backgroundColor = '';
    }
  } else {
    root.style.background = bg;
    if (body) body.style.background = bg;
  }
  root.style.colorScheme = isDark ? 'dark' : 'light';
  if (body) body.style.colorScheme = isDark ? 'dark' : 'light';
  applyBrandingThemeColor(isDark);
  const mcs = document.querySelector('meta[name="color-scheme"]');
  if (mcs) mcs.content = isDark ? 'dark light' : 'light dark';

  const btn = document.getElementById('darkModeToggle');
  const icon = document.getElementById('darkModeIcon');
  if (icon) icon.textContent = isDark ? 'light_mode' : 'dark_mode';
  if (btn) {
    const ttOn = (typeof t === 'function' ? t('switch_to_dark_mode') : 'Switch to dark mode');
    const ttOff = (typeof t === 'function' ? t('switch_to_light_mode') : 'Switch to light mode');
    const aria = (typeof t === 'function' ? (isDark ? t('light_mode') : t('dark_mode')) : (isDark ? 'Light mode' : 'Dark mode'));
    btn.classList.toggle('active', isDark);
    btn.setAttribute('aria-label', aria);
    btn.setAttribute('title', isDark ? ttOff : ttOn);
  }
}

function bindDarkMode() {
  const btn = document.getElementById('darkModeToggle');