@media screen and (max-width: 700px) {
  header {
    flex-wrap: wrap;
    justify-content: center;
    padding: 8px 5%;
  }

  header .site-name {
    font-size: 2rem;
    padding-left: 0;
  }

  header ul {
    justify-content: center;
  }

  footer {
    margin-top: 12px;
  }

  .main {
    flex-direction: column;
    margin: 0 5%;
    gap: 16px;
  }

  .content {
    font-size: 100%;
    padding: 0;
  }

  /* flex-basis would size the height once .main is a column */
  aside {
    flex: none;
  }
}