html {
    font-size: 12pt;
}

@media (min-width:640px) {

    html {font-size:16pt;}

    .two-columns-example {
        display: flex;
    }

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

img {
    max-width: 100%;
}

body {
    margin-left: auto;
    margin-right: auto;
    width: 90%;
    max-width: 40rem;
}