@media (max-width: 768px) {
    .container_content {
        width: 100%;
    }
    .sidebar {
        width: 100%;
    }

    .content {
        width: calc(100% - 2 * 25px);
    }

    header {
        background-image: url(/media/images/head_klein.svg);
        background-size: auto 70px;
        background-position: 10px 13px;
        height: 85px;
    }

    body {
        display: flex;
        overflow-x: hidden;
        height: inherit;
    }

    #the_navi {
        width: calc(100vw - 45px - 25px);
        padding-left: 39px
    }

    .content {
        margin-bottom: 0;
    }

    footer {
        display: block;
    }
}