html{
    font-size: 12pt;
}

@media (min-width: 640px) {
    html{
        font-size: 16pt;
    }
}

img{
    max-width: 100%;
}

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

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

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