html,
body {
    height: 100%;
    width: 100%;
    background-color: #FFFFFF;
}

.center {
    margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    margin-right: -50%;
    transform: translate(-50%, -50%)
}

.loader {
    display: flex;
    justify-content: center;
    align-items: center;
    margin-top: 20px;
}

.classic-4 {
  padding-bottom:5px;
  font-weight: bold;
  font-family: monospace;
  font-size: 30px;
  overflow: hidden;
  color:#0000;
  text-shadow: 0 0 0 #000,10ch 0 0 #000;
  background:linear-gradient(#000 0 0) bottom left/0% 3px no-repeat;
  animation:c4 1.5s infinite;
}
.classic-4:before {
  content:"Loading...";
}
@keyframes c4 {
    80%  {text-shadow:    0  0 0 #000,10ch 0 0 #000;background-size:100% 3px}
    100% {text-shadow: -10ch 0 0 #000,0    0 0 #000}
}

/**/
body {
  display: grid;
  grid-template-columns: repeat(auto-fit,minmax(250px,1fr));
  grid-auto-rows: 130px;
  place-items:center;
}

* {
  box-sizing: border-box;
}