/* ── Responsive ── */
@media (max-width: 900px) {
  .hero-inner {
    grid-template-columns: 1fr;
    gap: 3rem;
  }

  .hero-visual { order: -1; }

  .drawing-panel { transform: none; }

  .problem-grid,
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .step {
    grid-template-columns: 60px 1fr;
    gap: 1.25rem;
  }
}

@media (max-width: 640px) {
  .nav-toggle { display: flex; }

  .nav-links {
    position: fixed;
    top: 0;
    right: 0;
    width: min(280px, 85vw);
    height: 100vh;
    flex-direction: column;
    align-items: flex-start;
    padding: 5rem 2rem 2rem;
    background: var(--bg-surface);
    border-left: 1px solid var(--border);
    transform: translateX(100%);
    transition: transform var(--transition);
    gap: 1.5rem;
  }

  .nav-links.open { transform: translateX(0); }

  .form-row { grid-template-columns: 1fr; }

  .footer-inner {
    grid-template-columns: 1fr;
  }

  .footer-links { flex-wrap: wrap; }
}