/*-----------置顶按钮-----------*/
.to_top_btn {
  display: none;
  width:60px;
  height:60px;
  position: fixed;
  bottom: 20px;
  right: 0;
  background:#0078ff;
  border-radius: 5px;
  cursor: pointer;
}

.to_top_btn::before {
  content: ' ';
  display: block;
  position: relative;
  top: 25px;
  left: 20px;
  width: 20px;
  height: 20px;
  border-width: 2px 2px 0 0;
  border-style: solid;
  border-color: #fff;
  transform: rotate(-45deg);
}

.to_top_btn:hover{
  background: #fff;
}

.to_top_btn:hover::before{
  border-color: #0078ff;
}

/*-----------置顶按钮-----------*/