:root {
  --color-background: #cbddfb;
  --axis-x: 1px;
  --axis-y: 1rem;
  --delay: 10;
  --color-black: #000;
  --color-white: #fff;
  --color-orange: #ff901f;
  --color-red: #ff2975;
  --color-violet: #f222ff;
  --color-blue: #8c1eff;
  --color-green: #5acb3c;
  --color-yellow: #ffd319;
  --color-foreground: var(--color-white);
  --font-name: Righteous;
}

html,
body {
  font-size: 20px;
  font-family: var(--font-name);
}

body {
  background-color: var(--color-background);
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-name);
  height: 100vh;
}
.c-rainbow {
  counter-reset: rainbow;
  position: relative;
  display: block;
  list-style: none;
  padding: 0;
  margin: 0;
}
.c-rainbow__layer {
  --text-color: var(--color-foreground);
  counter-increment: rainbow;
  font-size: 3rem;
  color: var(--text-color);
  text-shadow: -1px -1px 0 var(--color-black), 1px -1px 0 var(--color-black),
    -1px 1px 0 var(--color-black), 1px 1px 0 var(--color-black),
    4px 4px 0 rgba(0, 0, 0, 0.2);
  animation: rainbow 1.5s ease-in-out infinite;
}
.c-rainbow__layer:nth-child(1) {
  animation-delay: calc(1 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 1);
  z-index: -10;
}
.c-rainbow__layer:nth-child(2) {
  animation-delay: calc(2 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 2);
  z-index: -20;
}
.c-rainbow__layer:nth-child(3) {
  animation-delay: calc(3 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 3);
  z-index: -30;
}
.c-rainbow__layer:nth-child(4) {
  animation-delay: calc(4 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 4);
  z-index: -40;
}
.c-rainbow__layer:nth-child(5) {
  animation-delay: calc(5 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 5);
  z-index: -50;
}
.c-rainbow__layer:nth-child(6) {
  animation-delay: calc(6 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 6);
  z-index: -60;
}
.c-rainbow__layer:nth-child(7) {
  animation-delay: calc(7 / var(--delay) * 1s);
  left: calc(var(--axis-x) * 7);
  z-index: -70;
}
.c-rainbow__layer:not(:first-child) {
  position: absolute;
  top: 0;
}
.c-rainbow__layer--white {
  --text-color: var(--color-white);
}
.c-rainbow__layer--orange {
  --text-color: var(--color-orange);
}
.c-rainbow__layer--red {
  --text-color: var(--color-red);
}
.c-rainbow__layer--violet {
  --text-color: var(--color-violet);
}
.c-rainbow__layer--blue {
  --text-color: var(--color-blue);
}
.c-rainbow__layer--green {
  --text-color: var(--color-green);
}
.c-rainbow__layer--yellow {
  --text-color: var(--color-yellow);
}

@keyframes rainbow {
  0%,
  100% {
    transform: translatey(var(--axis-y));
  }
  50% {
    transform: translatey(calc(var(--axis-y) * -1));
  }
}