Animated Aurora

1<div class="scene">
2  <div class="band b1"></div>
3  <div class="band b2"></div>
4</div>
5
6<style>
7  .scene{position:relative;width:440px;height:260px;border-radius:20px;overflow:hidden;background:#070710}
8  .band{position:absolute;width:160%;height:70px;left:-30%;filter:blur(30px);opacity:.6;border-radius:50%}
9  .b1{top:60px;background:linear-gradient(90deg,#8b5cf6,#d946ef,#06b6d4);animation:sway 7s ease-in-out infinite}
10  .b2{top:130px;background:linear-gradient(90deg,#06b6d4,#8b5cf6);animation:sway 9s ease-in-out infinite reverse}
11  @keyframes sway{0%,100%{transform:translateX(-30px) rotate(-4deg)}50%{transform:translateX(30px) rotate(4deg)}}
12</style>