@media (max-width: 800px) {
    body {
        font-size: 1.2em;
    }
    .overall,
    .viewer,
    .content,
    .submenu,
    .middle,
    nav.topmenu,
    #map {
        width: 100%;
    }
    .leftside,
    .rightside {
        display: none;
    }
    img {
        max-width: 100%;
        height: auto;
    }
}

@media (max-width: 560px) {
    nav.topmenu {
        font-size: 1.4em;
    }
    nav.topmenu ul {
        display: block;
    }
    nav.topmenu ul li {
        display: inline;
        border-bottom: 1px solid #ccc;
    }
    nav.topmenu ul li a {
        display: inline;
    }
    .optional {
        display: none;
    }
}