#up
{
    right: 10px;
    bottom: 50px;
    z-index: 1000;
    position: fixed;
}

#up button
{
    width: 40px;
    height: 40px;
    border-radius: 50%;
}

@media( max-width: 1000px )
{
    #up
    {
        bottom: 10px;
    }
}