#backto {
    position: fixed;
    z-index: 1000;
    width: 160px;
    height: 50px;
    opacity: 1;
    transition: opacity 0.2s;
    cursor: pointer;
}

#backto img {
    width: 100%;
    height: 100%;
    margin-top: 20px;
    margin-left: 20px;
}