@keyframes bg {
    0% {
      background-position: 0 0;
    }
    100% {
      background-position: -100% 10;
    }
  }

.animated-bg {
    background: radial-gradient(circle at center, #0A002F 20%, rgba(0,0,0,0.45) 100%),
        url("https://images.unsplash.com/photo-1454789548928-9efd52dc4031?ixlib=rb-1.2.1&auto=format&fit=crop&w=580&q=80");
    background-size: 150% 150%;
    background-position: center;
    animation: bg 20s infinite linear alternate-reverse;
}