html{
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; }
  }
 
 @media (min-width: 640px) {
    .two-columns-example {
        display: flex;}

    .two-columns-example > * {
     width: 50%; }
}
}