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

.loader {
  width: fit-content;
  font-weight: bold;
  font-family: cursive;
  font-size: 40px;
  padding-bottom: 10px;
  background: linear-gradient(currentColor 0 0) 0 100%/0% 3px no-repeat;
  animation: loading 2s linear infinite;
}

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

@keyframes loading {
  to {
    background-size: 100% 3px;
  }
}