#scrollToTopButton {
  display: block;
  z-index: 99;
  transition: background-color 0.3s, opacity 0.5s, visibility 0.5s;
  opacity: 0;
  visibility: hidden;
  position: fixed;
  bottom: 52px;
  right: 30px;
  border: none;
  border-radius: 4px;
  outline: none;
  width: 50px;
  height: 50px;
  padding: 8px;
  background-color: #21313a;
}
#scrollToTopButton i {
  color: white;
}
#scrollToTopButton:hover,
#scrollToTopButton:focus,
#scrollToTopButton:focus-within {
  cursor: pointer;
  background-color: #0078b4;
}

html {
  scroll-behavior: smooth;
}