.back-to-top {
  position: fixed;
  right: 20px;
  bottom: 30px;
  text-align: center;
  z-index: 9999;
  border-radius: 50%;
  width: 50px;
  height: 50px;
  line-height: 50px;
  padding: 0;
  font-size: 25px;
  opacity: 0;
  cursor: pointer;
  color: #ffffff;
  background-color: #007bff;
  transform: translateY(20px);
  transition: opacity 0.4s ease, transform 0.4s ease, visibility 0.4s;
}

.back-to-top.show {
  opacity: 1;
  color: #ffffff;
  visibility: visible;
  transform: translateY(0);
}

.back-to-top:hover {
  color: #ffffff;
  background-color: #0056b3;
  transform: translateY(-2px) scale(1.05);
}