ChrisWright Looks like it's this CSS for anyone looking to do the same. Quite creative really... 🙂
.IndexPage-newDiscussion {
background: linear-gradient(124deg,#ff2400,#e81d1d,#e8b71d,#e3e81d,#1de840,#1ddde8,#2b1de8,#dd00f3,#dd00f3);
color: #fff;
background-size: 1800% 1800%;
-webkit-animation: rainbow 15s ease infinite;
-z-animation: rainbow 15s ease infinite;
-o-animation: rainbow 15s ease infinite;
animation: rainbow 15s ease infinite;
}