.aurora-bg::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 100%;
  background: linear-gradient(120deg, #e74c3c, #f39c12, #8e44ad, #2980b9);
  background-size: 400% 400%;
  animation: auroraBG 10s ease infinite;
}

@keyframes auroraBG {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}