.footer {
    position: fixed;
    bottom: 0;
    right: 0;
    height: 56px;
    color: #222;
    background-color: #fff;
    justify-content: space-around;
    box-shadow: 0px -6px 6px 0px rgba(0, 0, 0, 0.1);
    align-items: center;
    display: none;
    left: 0;
}

.footer a {
    padding-top: 5px;
    font-size: 14px;
    flex: 1;
    text-align: center;
    transition: background-color 0.3s;
}

.footer a i[class^="icon-"] {
    display: block;
    font-size: 32px;
}

.footer a:not(.active) {
    opacity: 0.75;
}

@media only screen and (max-width: 900px) {
    .footer {
        display: flex;
    }
    .site-content {
        bottom: 56px;
    }
}

@media only screen and (max-width: 900px) {
    #planning-content,
    #homework-content,
    #resources-content,
    #works-advancement-content,
    #works-discount-content {
        display: none;
    }
    #planning:target~div #planning-content,
    #homework:target~div #homework-content,
    #resources:target~div #resources-content,
    #works-advancement:target~div #works-advancement-content,
    #works-discount:target~div #works-discount-content {
        display: block;
    }
    #planning:target~.footer a:nth-child(1),
    #homework:target~.footer a:nth-child(2),
    #resources:target~.footer a:nth-child(3),
    #works-advancement:target~.footer a:nth-child(1),
    #works-discount:target~.footer a:nth-child(2) {
        opacity: 1;
        background-color: #eee;
    }
    #planning-content {
        min-width: unset;
    }
}