body {
  height: 100vh;
  overflow: hidden;
  display: grid;
  place-items: center;
}

.loader {
  width: fit-content;
  font-size: 40px;
  font-family: monospace;
  font-weight: bold;
  text-transform: uppercase;
  color: #0000;
  -webkit-text-stroke: 1px #000;
  --g: conic-gradient(#000 0 0) no-repeat text;
  background: var(--g) 0, var(--g) 1ch, var(--g) 2ch, var(--g) 3ch, var(--g) 4ch,
    var(--g) 5ch, var(--g) 6ch;
  background-position-y: 100%;
  animation: fill 1.5s linear infinite alternate;
}

.loader::before {
  content: "Loading";
}

@keyframes fill {
  0% {
    background-size: 1ch 0, 1ch 0, 1ch 0, 1ch 0, 1ch 0, 1ch 0, 1ch 0;
  }

  25% {
    background-size: 1ch 100%, 1ch 50%, 1ch 0, 1ch 0, 1ch 0, 1ch 50%, 1ch 100%;
  }

  50% {
    background-size: 1ch 100%, 1ch 100%, 1ch 50%, 1ch 0, 1ch 50%, 1ch 100%,
      1ch 100%;
  }

  75% {
    background-size: 1ch 100%, 1ch 100%, 1ch 100%, 1ch 50%, 1ch 100%, 1ch 100%,
      1ch 100%;
  }

  to {
    background-size: 1ch 100%, 1ch 100%, 1ch 100%, 1ch 100%, 1ch 100%, 1ch 100%,
      1ch 100%;
  }
}