.back{
    content: '';
    position: fixed;
    height: 60px;
    width: 65px;
    padding: 5px;
    top: 50px;
    border-radius: 0 10px 10px 0;
    background: #212121;
    overflow: hidden;
    z-index: 999;
    transition: 1s ease;
}

.back a{
    text-decoration: none;
    text-transform: uppercase;
    font-weight: bold;
    color: #fff;
}

.back:hover{
    width: 270px;
}

.back img{
    height: 100%;
    max-width: 50px;
    margin-right: 10px;
}

.back span.back-text{
    opacity: 0;
    transition: 2s ease;
}

.back:hover span.back-text{
    opacity: 1;
}

@media (max-width: 767px) {
    .back{
        height: 50px;
        top: auto;
        bottom: 0px;
        width: fit-content;
        border-radius: 0 10px 0 0;
    }

    .back span.back-text{
        opacity: 1;
        margin-right: 15px;
    }
}