img { max-width: 100%; }
body{
    margin-left: auto; margin-right: auto;
    width: 90%;
    max-width: 40rem;
}
html { font-size: 12pt; }

  @media (min-width: 640px) {
    html { font-size: 16pt; }
    .two-columns-example{
        display: flex;
    }
    .two-columns-example > *{width: 50%;}
  }