.to-top-btn {
  position: fixed;
  bottom: 20px;
  right: 20px;
  width: 50px;
  height: 50px;
  border: none;
  background-color: #de0404;
  box-shadow: 0 0 5px rgba(0, 0, 0, 0.17);
  font-size: 22px;
  font-weight: 700;
  border-radius: 5px;
  cursor: pointer;
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.3s ease, visibility 0.3s ease, box-shadow 0.5s ease,
    background 0.5s ease;
  z-index: 999;
}

.to-top-btn:hover {
  background: #ef4623;
}

.to-top-btn.active {
  opacity: 1;
  visibility: visible;
}