/* ============================================
   Responsive Design
   ============================================ */

/* Tablet: 768px - 1200px */
@media (max-width: 1200px) {
  .modules-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .data-dashboard__stats {
    grid-template-columns: repeat(2, 1fr);
  }

  .trust-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .footer__grid {
    grid-template-columns: 1fr 1fr;
    gap: var(--space-8);
  }

  .advantages-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .page-highlights__grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .demo-grid {
    grid-template-columns: 1fr !important;
  }
}

/* Mobile: < 768px */
@media (max-width: 768px) {
  :root {
    --text-5xl: 2rem;
    --text-4xl: 1.75rem;
    --text-3xl: 1.5rem;
    --nav-height: 64px;
  }

  .section {
    padding: var(--space-16) 0;
  }

  /* Navigation: hamburger */
  .nav__menu {
    display: none;
  }

  .nav__hamburger {
    display: flex;
  }

  .nav__mobile-menu {
    display: flex;
  }

  .nav__hamburger--active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
  }
  .nav__hamburger--active span:nth-child(2) {
    opacity: 0;
  }
  .nav__hamburger--active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
  }

  /* Hero */
  .hero__actions {
    flex-direction: column;
  }

  .hero__actions .btn {
    width: 100%;
  }

  /* Intro */
  .intro__grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .intro__visual {
    min-height: 200px;
  }

  /* Modules */
  .modules-grid {
    grid-template-columns: 1fr;
  }

  /* Data Dashboard */
  .data-dashboard__stats {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-4);
  }

  .data-dashboard__stat-number {
    font-size: var(--text-3xl);
  }

  /* Devices */
  .devices__showcase {
    flex-direction: column;
    align-items: center;
  }

  .device--signage .device__frame {
    width: 240px;
  }

  .device--signage .device__screen {
    aspect-ratio: 770 / 434;
  }

  .device--teacher .device__screen {
    aspect-ratio: 1256 / 2760;
  }

  .device--student .device__screen {
    aspect-ratio: 1254 / 2343;
  }

  .device--desktop .device__frame {
    width: 300px;
  }

  .device--desktop .device__screen {
    height: 180px;
  }

  /* Trust grid */
  .trust-grid {
    grid-template-columns: 1fr;
  }

  /* Architecture */
  .architecture__layer {
    padding: var(--space-4) var(--space-5);
  }

  .architecture__layer-desc {
    font-size: var(--text-xs);
  }

  /* Advantages */
  .advantages-grid {
    grid-template-columns: 1fr;
  }

  /* Footer */
  .footer__grid {
    grid-template-columns: 1fr;
    gap: var(--space-8);
  }

  .footer__bottom {
    flex-direction: column;
    gap: var(--space-3);
    text-align: center;
  }

  /* Feature list (sub-pages) */
  .feature-list__grid {
    grid-template-columns: 1fr;
  }

  .page-highlights__grid {
    grid-template-columns: 1fr;
  }

  /* Demo page */
  .demo-grid {
    grid-template-columns: 1fr !important;
  }

  /* Floating: show phone CTA, hide chat FAB */
  .fab-chat {
    bottom: 80px;
    right: var(--space-4);
    width: 50px;
    height: 50px;
  }

  .fab-phone {
    display: block;
  }

  /* Page bottom CTA */
  .page-bottom-cta {
    flex-direction: column;
  }
}