https://thecastlemap.com/theme.js

1/* Castlemap theme switch — dark is the site's identity and the default;
2   "light" is a per-visitor opt-in remembered in localStorage. Loaded in
3   <head> WITHOUT defer (the CSP is script-src 'self', so no inline scripts)
4   so a stored choice applies before first paint. Clicks are DELEGATED, so
5   .themetoggle buttons the map SPA mounts later work too; every flip
6   dispatches "castlemap:theme" for the map canvas to repaint itself. */
7(function () {
8  function tint(light) {
9    var m = document.querySelector('meta[name="theme-color"]');
10    if (m) m.setAttribute('content', light ? '#f4efe2' : '#0a0f14');
11  }
12  var light = false;
13  try { light = localStorage.getItem('castlemap.theme') === 'light'; } catch (e) {}
14  if (light) { document.documentElement.classList.replace('dark', 'light'); tint(true); }
15  document.addEventListener('click', function (e) {
16    var t = e.target;
17    var b = t && t.closest ? t.closest('.themetoggle') : null;
18    if (!b) return;
19    var h = document.documentElement, l = h.classList.toggle('light');
20    h.classList.toggle('dark', !l);
21    tint(l);
22    try { localStorage.setItem('castlemap.theme', l ? 'light' : 'dark'); } catch (e2) {}
23    try { document.dispatchEvent(new CustomEvent('castlemap:theme', { detail: { light: l } })); } catch (e2) {}
24  });
25})();