#backToTopBtn{position:fixed;bottom:40px;right:30px;width:48px;height:48px;padding:0;border:none;border-radius:50%;background:0 0;cursor:pointer;box-shadow:0 4px 12px rgba(0,0,0,.2);z-index:99999;opacity:0;visibility:hidden;transition:opacity .3s,visibility .3s,transform .3s}#backToTopBtn.show{opacity:1;visibility:visible}#backToTopBtn:hover{transform:translateY(-4px)}#backToTopBtn img{width:100%;height:100%;object-fit:contain;border-radius:50%}