@media screen and (max-width: 660px) {
    .hide-660 { display: none !important; }
    H2 { font-size: 1.1em; }

    HEADER DIV#main-nav { flex-direction: column; }
    HEADER DIV#main-nav a { text-align: center; padding: 1.2em; }




    SECTION#relan-introduction IMG {
        width: 100%;
        border-width: 0.6em;
    }

    SECTION#relan-book DIV.divider-2 { flex-direction: column; }
    SECTION#relan-book IMG { width: 85%; margin: 0 auto; }
}