/* all回頂端按鈕 */
.fixed_btn{
  height: 0; left: 0; right: 0; bottom: 0;
  position: -webkit-sticky; position: sticky;
  z-index: 99;
}

.go_top{
  width:fit-content; height: fit-content;
  position: absolute; right: 0; bottom: 21px; z-index: 99;  
  transform-origin: bottom;
  transform: translateX(100%);
  opacity: 0;
}

.fixed_btn.active .go_top{ transform: translateX(-50%); opacity:.5;}

.go_top .btn{width:42px; height: 42px;
  background-color:rgba(230, 230, 230, 1);
  border-radius:21px; border:5px solid var(--block-title-color-wt-bg);
  transform-origin: bottom;
}

.go_top svg{
  width: 100%; height: 100%;
  mask-image: url(../images/svg/up.svg); mask-repeat: no-repeat;
  background-color:var(--block-title-color-wt-bg);
}

.fixed_btn.active .go_top::before{
  content:""; width:4px; height:0; background-color:rgba(34,34,36,1); display: block;
  position: absolute; left:50%; top:30%; z-index: 1;
  transform: translateX(-50%); transform-origin:top; border-radius:2px; transition: .2s;
}
/* .fixed_btn.active .go_top::after{
  content:""; width:100%; height:100%;
  position: absolute; left:0; top:0; z-index: 10; cursor: pointer;
}
 */
@media (hover) {
  .fixed_btn.active .go_top:hover .btn{ height:60px; filter:brightness(1.5) contrast(1.5);}
  .fixed_btn.active .go_top:hover:before{ height:50%; top:28%;}
}

@media (max-width:800px){ 
  /* 回頂端按鈕 */

  .fixed_btn .btn{width:38px; height:38px; border-radius:19px; border-width:4px;}
  .fixed_btn.active .go_top::before{width:3px; top:30%;}

  @media (hover) {
    .fixed_btn.active .go_top:hover:before{ top:25%;} 
  } 
}