<div class="container">
  <div class="text">
    <span style="--i:0">H</span>
    <span style="--i:1">a</span>
    <span style="--i:2">p</span>
    <span style="--i:3">p</span>
    <span style="--i:4">y</span>
    <span style="--i:5"></span>
    <span style="--i:6">X</span>
    <span style="--i:7">'</span>
    <span style="--i:8">m</span>
    <span style="--i:9">a</span>
    <span style="--i:10">s</span>
  </div>
</div>

* {
  padding: 0;
  margin: 0;
  box-sizing: border-box;
}

.container {
  width: 100%;
  min-height: 100vh;
  position: relative;
  display: flex;
  justify-content: center;
  align-items: center;
  background: linear-gradient(
    90deg,
    hsla(59, 86%, 68%, 1) 0%,
    hsla(134, 36%, 53%, 1) 100%
  );
}

.text span {
  color: hsla(59, 86%, 68%, 1);
  font-size: 60px;
  display: inline-block;
  text-align: center;
  width: 60px;
  text-transform: uppercase;
  transfrom: translateZ(0px), translateY(0px);
  animation: shadowEffect 2s ease-in-out infinite;
  animation-delay: calc(200ms * var(--i));
}

@keyframes shadowEffect {
  0%,
  100% {
    text-shadow: 0 0 #000;
    transform: translateY(0);
  }
  50% {
    text-shadow: 0 1px #f00, 0 2px #f00, 0 3px #f00, 0 4px #f00, 0 5px #f00,
      0 6px #f00, 0 7px #f00, 0 8px #f00, 0 9px #f00, 0 10px #f00;
    transform: translateY(-20px);
  }
}