class CustomNavbar extends HTMLElement { connectedCallback() { this.attachShadow({ mode: 'open' }); this.shadowRoot.innerHTML = ` `; const menuBtn = this.shadowRoot.querySelector('.menu-btn'); const menu = this.shadowRoot.querySelector('ul'); menuBtn.addEventListener('click', () => { menu.classList.toggle('active'); }); } } customElements.define('custom-navbar', CustomNavbar);