/*  
---------------------------------------------------
Back to top
---------------------------------------------------  
*/

.usn_back-to-top { 
    display:block;
    transition: bottom 0.3s ease-in-out 0s, opacity 0.3s ease-in-out 0s, box-shadow 0.3s ease-in-out 0s;
}
.usn_back-to-top .btn i { 
    position:absolute; top:50%; left:50%;
    transform:translate(-50%,-50%);
}