/* Mobile (less than or equal to 599px) */
@media (max-width: 599px) {
  .container { padding: 1rem; }
  .grid { display: grid; gap: 1rem; }
  .grid.cols-2, .grid.cols-3 { grid-template-columns: 1fr; }
  nav a { padding: .6rem .7rem; }
  .card { padding: .9rem; }
  form.contact-form { max-width: 100%; }
  .brand { font-size: 1rem; }
}