.jn-wave {
  background: linear-gradient(-45deg, #2f3640, #e8e8e8, #718093, #bfbfbf);
  background-size: 400% 400%;
  animation: gradient 15s ease infinite;
  height: 100vh;
}
@keyframes gradient {
  0% {
    background-position: 0% 50%;
  }
  50% {
    background-position: 100% 50%;
  }
  100% {
    background-position: 0% 50%;
  }
}