class DarkModeToggle extends HTMLElement { connectedCallback() { this.innerHTML = ` `; this.querySelector('#dark-mode-toggle').addEventListener('click', () => { document.documentElement.classList.toggle('dark'); localStorage.setItem('darkMode', document.documentElement.classList.contains('dark')); }); // Initialize from localStorage if (localStorage.getItem('darkMode') === 'true') { document.documentElement.classList.add('dark'); } } } customElements.define('dark-mode-toggle', DarkModeToggle);