Aurora

Color bands mimicking aurora borealis.

.aurora { background:linear-gradient(135deg,#0c0c1d,#1a0b2e); position:relative; overflow:hidden; }
.aurora::before,.aurora::after { content:""; position:absolute; width:300px; height:300px; border-radius:50%; filter:blur(80px); animation:adr 8s ease-in-out infinite alternate; }
.aurora::before { background:#8b5cf680; top:-100px; left:20%; }
.aurora::after { background:#06b6d460; bottom:-100px; right:20%; animation-delay:-4s; }
@keyframes adr { to { transform:translate(50px,30px) scale(1.2); } }