#back-to-top {
  position: fixed;
  bottom: 30px;
  left: 30px;
  width: 55px;
  height: 55px;
  background: linear-gradient(135deg, #020074, #09033d);
  color: white;
  border: none;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  box-shadow: 0 8px 25px rgba(107, 70, 193, 0.4);
  transition: all 0.3s ease;
  z-index: 9999;
  opacity: 0;
  transform: translateY(20px);
}

#back-to-top:hover {
  transform: scale(1.1);
  box-shadow: 0 12px 30px rgba(107, 70, 193, 0.5);
  background: linear-gradient(135deg, #020074, #09033d);
}

#back-to-top.show {
  display: flex;
  opacity: 1;
  transform: translateY(0);
}

/* Efecto de brillo */
#back-to-top::before {
  content: '';
  position: absolute;
  inset: -4px;
  background: inherit;
  border-radius: 50%;
  filter: blur(8px);
  opacity: 0.3;
  z-index: -1;
}