@media screen and (min-width: 640px) {

    .navigation {
        display: flex;
    }

    .navigation li {
        display: block;
        flex: 1 1 100%;
    }

    .navigation a {
        text-align: center;
    }

    #menu {
        display: none;
    }

    main {
        display: grid;
        grid-template-columns: 1fr;
        grid-gap: 10px;
        margin: 100px 20%;
    }

    h2 {
        grid-column: 1 / -1;
        text-align: center;
        width: 100%;
        margin-bottom: 0;
        padding-top: 50px;
    }

}