#TopSpeed {
    display: block;
    position: fixed;
    bottom: 20px;
    right: 20px;
    font-size: 48px;
}
#TopSpeed {
    transition: all 0.5s ease 0s;
    -moz-transition: all 0.5s ease 0s;
    -webkit-transition: all 0.5s ease 0s;
    -o-transition: all 0.5s ease 0s;
    opacity: 0.5;
    display:none;
    cursor: pointer;
}
#TopSpeed:hover {
    opacity: 1;
}