#green-back-to-top{
position:fixed;
right:16px;
bottom:80px;
width:44px;
height:44px;
border-radius:50%;
background:#0a7c5a;
color:#fff;
display:flex;
align-items:center;
justify-content:center;
font-size:20px;
cursor:pointer;
opacity:0;
visibility:hidden;
transition:opacity .3s;
z-index:9999;
}
#green-back-to-top.is-show{
opacity:1;
visibility:visible;
}