.glowing-button {
  --borderWidth: 10px;
  background: var(--primary-color);
  position: relative;
  color: white;
  border-radius: calc(15px - var(--borderWidth));
}

.glowing-button:after {
  content: '';
  position: absolute;
  top: calc(-1 * var(--borderWidth));
  left: calc(-1 * var(--borderWidth));
  height: calc(100% + var(--borderWidth) * 2);
  width: calc(100% + var(--borderWidth) * 2);
  background: linear-gradient(60deg, red, white, blue);
  border-radius: 15px;
  z-index: -1;
  animation: animatedgradient 1.5s alternate infinite;
  background-size: 300% 300%;
}


@keyframes animatedgradient {
	0% {
		background-position: 0% 50%;
	}
	50% {
		background-position: 100% 50%;
	}
	100% {
		background-position: 0% 50%;
	}
}