#scrollUp {
    bottom: 15px;
    right: 15px;
    background-color: #999;
    color: #fff;
    font-size: 12px;
    font-family: sans-serif;
    text-decoration: none;
    opacity: .7;
    padding: 8px 12px;
    -webkit-border-radius: 16px;
    -moz-border-radius: 16px;
    border-radius: 16px;
    -webkit-transition: background 200ms linear;
    -moz-transition: background 200ms linear;
    -o-transition: background 200ms linear;
    transition: background 200ms linear;
    -webkit-backface-visibility: hidden;
}

#scrollUp:hover {
    background-color: #000;
}