This could be used to animate gradient backgrounds on large buttons/CTAs

animated-gradient.scss

//Animated gradient background
//https://medium.com/@dave_lunny/animating-css-gradients-using-only-css-d2fd7671e759

//Usage: 
//Example 1: include gradientAnimation(red, blue, .6s);
//Example 2: include gradientAnimation(lighten($orange, 10), $orange, .6s);

@mixin gradientAnimation( $start, $end, $transTime ){
  background-size: 100%;
  background-image: linear-gradient($start, $end);
  position: relative;
  z-index: 100;
  &:before {
    background-image: linear-gradient($end, $start);
    content: "";
    display: block;
    height: 100%;
    position: absolute;
    top: 0; left: 0;
    opacity: 0;
    width: 100%;
    z-index: -100;
    transition: opacity $transTime;
  }
  &:hover {
     &:before {
       opacity: 1;
     }
  }
}