/* HTML: <div class="loader"></div> */
.loader {
  display: inline-flex;
  border: 2px solid #000;
  --c: no-repeat linear-gradient(#000 0 0) 50%;
  background: var(--c) calc(50% - 5px)/5px 5px,
    var(--c) calc(50% + 5px)/5px 5px;
}

.loader::before,
.loader::after {
  content: "12 00 23 40 31 45 60 17 45 32 29 42 50 08 14 07 46 11 03 55";
  font-size: 30px;
  font-family: monospace;
  font-weight: bold;
  line-height: 1em;
  height: 1em;
  width: 2ch;
  color: #0000;
  text-shadow: 0 0 0 #000;
  overflow: hidden;
  margin: 5px 10px;
  animation: l3 1s steps(20) infinite;
}

.loader::before {
  animation-duration: 1.5s;
}

@keyframes l3 {
  100% {
    text-shadow: 0 -20em 0 #000
  }
}