.pagetop {
 display: none;
 position: fixed;
 bottom: 30px;
 right: 150px;
 width:60px;
 height:70px;
 z-index: 999;
}


.pagetop img {
 display: block;
 width:60px;
 height:70px;
 filter: brightness(1) invert(0); 
}
 
.pagetop img:hover {
 display: block;
 width:60px;
 height:70px;
 opacity: 0.2;
}