body {
  margin: 0;
  background: #121214;
  height: 100vh;
  display: grid;
  place-items: center;
  overflow: hidden;
}

.rune {
  font: bold 240px sans-serif;
  user-select: none;
  color: #ffffff;
  filter: url(#iceGlow);
  animation: glacialPulse 4s ease-in-out infinite alternate;
}

@keyframes glacialPulse {
  0% {
    text-shadow:
      0 0 15px hsla(205, 100%, 75%, 0.8),
      0 0 30px hsla(205, 95%, 60%, 0.4);
  }
  100% {
    text-shadow:
      0 0 25px hsla(210, 100%, 80%, 0.9),
      0 0 45px hsla(210, 100%, 65%, 0.6);
  }
}