@keyframes rotate{to{transform:rotate(1turn)}}.rainbow-button{background:#e0a4584d}.rainbow-button:before{content:"";z-index:-2;filter:blur(6px);opacity:0;background-image:linear-gradient(#e0a458,#f5b041,#e0a458);background-position:100%;background-repeat:no-repeat;background-size:50% 30%;width:200%;height:200%;transition:opacity .3s;position:absolute;top:-50%;left:-50%}.rainbow-button:hover:before{opacity:1;animation:2s linear infinite rotate}