Link Hover Animation Background - https://css-tricks.com/4-ways-to-animate-the-color-of-a-text-link-on-hover/

style.css

a {
  position: relative;
  display: inline-block;
  font-size: 2em;
  font-weight: 800;
  color: royalblue;
  overflow: hidden;
  background: linear-gradient(to right, midnightblue, midnightblue 50%, royalblue 50%);
  background-clip: text;
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-size: 200% 100%;
  background-position: 100%;
  transition: background-position 275ms ease;
  text-decoration: none; // text decorations are clipped in WebKit browsers
  &:hover {
    background-position: 0 100%;
  }
}