/* Mathew's theme handshake with the wiki (see mathew.css, its stylesheet).
 *
 * The wiki opens this frame as ?theme=light|dark — the editor cannot see
 * the page around it (another origin), but it can at least open wearing
 * the same mood. Without the parameter — a direct visit — the browser's
 * preference decides, the same rule lean4web follows for its own default.
 *
 * Runs synchronously in <head>, before the first paint, so the page never
 * flashes the wrong palette; <html data-mathew-theme> is the hook the
 * stylesheet's overrides hang on. */
(function () {
  var param = null
  try {
    param = new URLSearchParams(window.location.search).get('theme')
  } catch (e) {
    /* an engine without URLSearchParams gets the fallback below */
  }
  var theme = param === 'light' || param === 'dark'
    ? param
    : window.matchMedia && window.matchMedia('(prefers-color-scheme: dark)').matches
      ? 'dark'
      : 'light'
  document.documentElement.setAttribute('data-mathew-theme', theme)
})()