.pagetop {
  position: fixed;
  bottom: 20px;
  right: 20px;
}
.pagetop a {
  display: block;
  width: 40px;
  height: 40px;
  line-height: 35px;
  text-align: center;
  font-size: 20px;
  color: #fff;
  background: #3b71ca;
  border-radius: 50%;
  box-shadow: 0 1px 5px rgba(0, 0, 0, 0.2);
}