@charset "utf-8";

.back-top {
  position: fixed;
  background: #3a3a3a;
  right: 0;
  bottom: 0;
  z-index: 30;
}
.back-top a {
  display: block;
  height: 64px;
  width: 64px;
  position: relative;
}
.back-top a:after {
  content: "";
  width: 0;
  height: 0;
  border-style: solid;
  border-width: 0 12.5px 20px 12.5px;
  border-color: transparent transparent #ffffff transparent;
  position: absolute;
  top: 0;
  bottom: 0;
  right: 0;
  left: 0;
  margin: auto;
}