/* Slightly larger mobile typography, respecting the browser's default size. */
@media (max-width: 640px) {
  html { font-size: 106.25%; }
  body { font-size: 1rem; }
  .menu-toggle {
    width: 48px;
    height: 48px;
    min-width: 48px;
    min-height: 48px;
    flex-shrink: 0;
  }
  .menu-toggle .icon { width: 24px; height: 24px; }
}