// Back to Top Button Component
class BackToTopButton extends HTMLElement {
  connectedCallback() {
    this.innerHTML = `
      <button id="backToTopBtn" aria-label="Back to top" class="back-to-top" style="display:none;position:fixed;bottom:2rem;right:2rem;z-index:1000;padding:0.75em 1.5em;font-size:1.1rem;border-radius:2em;background:var(--color-primary,#3857BC);color:#fff;border:none;box-shadow:0 2px 8px rgba(0,0,0,0.15);cursor:pointer;transition:opacity 0.2s;">
        ↑ Top
      </button>
    `;
    const btn = this.querySelector('#backToTopBtn');
    window.addEventListener('scroll', () => {
      btn.style.display = window.scrollY > 300 ? 'block' : 'none';
    });
    btn.addEventListener('click', () => {
      window.scrollTo({ top: 0, behavior: 'smooth' });
    });
  }
}

export function registerBackToTopButton() {
  if (!customElements.get('back-to-top')) {
    customElements.define('back-to-top', BackToTopButton);
  }
}