@media (max-width: 900px) {
  .about-grid, .skills-grid, .projects-grid, .contact-grid { grid-template-columns: 1fr; }
  .certs-grid { grid-template-columns: 1fr 1fr; }
}
@media (max-width: 700px) {
  .nav-links { display: none; position: absolute; top: 100%; left: 0; width: 100%;
    flex-direction: column; background: rgba(11, 17, 32, 0.97); padding: 20px 40px;
    border-bottom: 1px solid var(--border-subtle); gap: 16px; align-items: flex-start;
  }
  .nav-links.open { display: flex; }
  .hamburger { display: flex; }
  .hero-content h1 { font-size: 2.2rem; }
  .certs-grid { grid-template-columns: 1fr; }
  .hero-btns { flex-direction: column; align-items: center; }
  section { padding: 70px 0; }
  .navbar { padding: 12px 20px; }
  .whatsapp-float { width: 48px; height: 48px; font-size: 1.3rem; bottom: 16px; right: 16px; }
}
@media (max-width: 480px) {
  .hero-content h1 { font-size: 1.8rem; }
  .section-title { font-size: 1.5rem; }
  .about-stats { grid-template-columns: 1fr; }
}