#back-to-top {
    outline: none;
    position: fixed;
    bottom: 100px;
    right: 35px;
    z-index: 9999;
    width: 32px;
    height: 32px;
    text-align: center;
    background: transparent;
    color: #8DC63F;
    cursor: pointer;
    border: #8DC63F 3px solid;
    text-decoration: none;
    opacity: 0;
    -webkit-border-radius: 50%;
       -moz-border-radius: 50%;
            border-radius: 50%;
    -webkit-transition: opacity 0.5s ease-out, position 0.7s ease-out;
       -moz-transition: opacity 0.5s ease-out, position 0.7s ease-out;
            transition: opacity 0.5s ease-out, position 0.7s ease-out;
}

#back-to-top:hover {
    color: #fff;
    background: #8DC63F;
}

#back-to-top.show {
    opacity: 0.5;
}

.fa-angle-up:before{
    font-size: 180%;
    font-weight: bold;
    line-height: 22px;
    content:"\f106";
}