JSFiddle - React, Tailwind, and code Playground

HTML

<input type="checkbox" id="random">
<label class="box" for="random"></label>

CSS

@property --c1{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c2{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c3{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c4{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c5{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c6{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}
@property --c7{
  syntax: '<integer>';
  inherits: false;
  initial-value: 1;
}

.box {
  --c:black; /* color */
  --s:0.5ch; /* space between numbers */
  --b:10px;  /* transparent border*/
  
  counter-set:c1 var(--c1) c2 var(--c2) c3 var(--c3) c3 var(--c3) c4 var(--c4) c5 var(--c5) c6 var(--c6) c7 var(--c7);

  display: table;
  margin:20px auto;
  font-size: 100px;
  letter-spacing: var(--s);
  font-family: monospace;
  color: #fff;
  background: 
    repeating-linear-gradient(to right, var(--c) 0 calc(1ch + var(--s) - var(--b)), transparent 0 calc(1ch + var(--s)))
    0 0/calc(100% - var(--s)/2 - 1px) 100% no-repeat;
  padding-left: calc((var(--s) - var(--b))/2);
  transform:translateX(calc(var(--s)/3)); /* rectify the centring */
  animation: c 1s infinite linear alternate;
  animation-name:    c1  ,c2  ,c3  ,c4  ,c5  ,c6  ,c7;
  animation-duration:0.10s,0.05s,0.02s,0.12s,0.13s,0.14s,0.08s;
  animation-play-state: running;
}

.box::before {
  content:
    counter(c1,upper-alpha) 
    counter(c2,upper-alpha) 
    counter(c3,upper-alpha) 
    counter(c4,upper-alpha) 
    counter(c5,upper-alpha) 
    counter(c6,upper-alpha) 
    counter(c7,upper-alpha)
}

@keyframes c1{to{--c1:26}}
@keyframes c2{to{--c2:26}}
@keyframes c3{to{--c3:26}}
@keyframes c4{to{--c4:26}}
@keyframes c5{to{--c5:26}}
@keyframes c6{to{--c6:26}}
@keyframes c7{to{--c7:26}}

input {opacity: 0.001}
input:checked + label {
  animation-play-state: paused;
}