@media (max-width: 768px) {
  nav a {
    margin: 0 0.5rem;
    font-size: 0.9rem;
  }

  iframe {
    height: 300px;
  }

  .logo img {
    width: 56px;
  }

  .section {
    margin: 4rem 1rem;
    padding: 3rem 2rem;
  }

    .card-layout {
    flex-direction: column;
  }

  .card-left, .card-right {
    flex: 1 1 100%;
  }

  .grid-layout .grid {
    grid-template-columns: 1fr;
  }
}