h1
  for letter, index in 'Cooool!'.split('')
    span(style=`--index: ${index}; --alpha-l: 0.125; --alpha-u: 0.25;`)= letter
View Compiled
@import url("https://fonts.googleapis.com/css2?family=Roboto+Mono:wght@699;700&display=swap");
:root {
  --lower: 100;
  --upper: 700;
}
body {
  min-height: 100vh;
  display: -webkit-box;
  display: flex;
  -webkit-box-align: center;
          align-items: center;
  -webkit-box-pack: center;
          justify-content: center;
  background: #262626;
}
h1 {
  font-family: 'Roboto Mono', monospace;
  font-size: 7rem;
  text-align: center;
  position: absolute;
  top: 50%;
  left: 50%;
  -webkit-transform: translate(-50%, -50%) translate(calc(var(--x, 0) * 1%), calc(var(--y, 0) * 1%));
          transform: translate(-50%, -50%) translate(calc(var(--x, 0) * 1%), calc(var(--y, 0) * 1%));
  font-variation-settings: 'wght' var(--lower);
  margin: 0;
}
h1 span {
  --hue: calc((360 / 7) * var(--index));
  color: hsl(var(--hue), 0%, 65%);
  -webkit-animation: rise 1s infinite cubic-bezier(0.5, 0, 0.5, 1);
          animation: rise 1s infinite cubic-bezier(0.5, 0, 0.5, 1);
  -webkit-animation-delay: calc((var(--index) - 7) * 0.1s);
          animation-delay: calc((var(--index) - 7) * 0.1s);
}
@-webkit-keyframes rise {
  50% {
    font-variation-settings: 'wght' var(--upper);
    color: hsl(var(--hue), 80%, 65%);
  }
}
@keyframes rise {
  50% {
    font-variation-settings: 'wght' var(--upper);
    color: hsl(var(--hue), 80%, 65%);
  }
}

External CSS

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External JavaScript

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