.scroll-top-button{
  position:fixed;
  right:18px;
  bottom:18px;
  width:52px;
  height:52px;
  border-radius:999px;
  border:1px solid #cfd7e4;
  background:#fff;
  color:#1f3f78;
  display:inline-flex;
  align-items:center;
  justify-content:center;
  font-size:28px;
  line-height:1;
  box-shadow:0 10px 26px rgba(15,23,42,.12);
  cursor:pointer;
  opacity:0;
  transform:translateY(8px);
  transition:opacity .2s ease,transform .2s ease,background .2s ease,border-color .2s ease;
  z-index:120;
}
.scroll-top-button:hover{
  background:#eef2f7;
  border-color:#c5cfdd;
}
.scroll-top-button.is-visible{
  opacity:1;
  transform:translateY(0);
}
.scroll-top-button[hidden]{
  display:none !important;
}
@media (max-width:640px){
  .scroll-top-button{
    right:14px;
    bottom:14px;
  }
}