#gtt_go-to-top a span {
display: none;
}
#gtt_go-to-top a {
background-image: url(//academialaboralonline.cl/wp-content/plugins/go-to-top/images/black-arrow.png);
background-position: left top;
width: 18px;
height: 19px;
display: block;
position:fixed;
bottom:10px;
right:10px;
cursor:pointer;
z-index: 100;
}
#gtt_go-to-top a:hover{
background-position: right top;
}