button {
  --border-radius: 15px;
  --border-width: 4px;
  appearance: none;
  position: relative;
  padding: 1em 2em;
  border: 0;
  background-color: #212121;
  font-family: "Roboto", Arial, "Segoe UI", sans-serif;
  font-size: 18px;
  font-weight: 500;
  color: #fff;
  z-index: 2;
}

button::after {
  --m-i: linear-gradient(#000, #000);
  --m-o: content-box, padding-box;
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  width: 100%;
  height: 100%;
  padding: var(--border-width);
  border-radius: var(--border-radius);
  background-image: conic-gradient(
		#D1ABE6,
		#9B59B6,
		#E5D9EC,
		#FFAFCC,
		#BDE0FE,
		#655adc,
		#488cfb
 );
  -webkit-mask-image: var(--m-i), var(--m-i);
  mask-image: var(--m-i), var(--m-i);
  -webkit-mask-origin: var(--m-o);
  mask-origin: var(--m-o);
  -webkit-mask-clip: var(--m-o);
  mask-composite: exclude;
  -webkit-mask-composite: destination-out;
  filter: hue-rotate(0);
  animation: rotate-hue linear 500ms infinite;
  animation-play-state: paused;
}

button:hover::after {
  animation-play-state: running;
}

@keyframes rotate-hue {
  to {
    filter: hue-rotate(1turn);
  }
}

button,
button::after {
  box-sizing: border-box;
}

button:active {
  --border-width: 5px;
}