@media only screen and (min-width: 60em) {
    header h1 {
        font-size: 2.5rem;
    }
    header h2 {
        font-size: 1.5rem;
    }
    main {
        grid-template-columns: 1fr 1fr 1fr;
    }
    section:nth-child(3) {
        grid-column: span 1;
    }
}