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%;
    }
  }