(function () {
  'use strict';

  const THEME_KEY = 'cms-theme';

  function initTheme() {
    const saved = localStorage.getItem(THEME_KEY);
    const prefersDark = window.matchMedia('(prefers-color-scheme: dark)').matches;
    const theme = saved || (prefersDark ? 'dark' : 'light');
    document.documentElement.setAttribute('data-theme', theme);

    const toggle = document.getElementById('theme-toggle');
    if (toggle) {
      toggle.addEventListener('click', function () {
        const current = document.documentElement.getAttribute('data-theme');
        const next = current === 'dark' ? 'light' : 'dark';
        document.documentElement.setAttribute('data-theme', next);
        localStorage.setItem(THEME_KEY, next);
      });
    }
  }

  document.addEventListener('DOMContentLoaded', initTheme);
})();