<div class="container">
<div class="flex">
<div class="loader">
</div>
</div>
<div class="load-text">
Loading...
</div>
</div>

.container {
  width: 100vw;
  height: 100vh;
  position: fixed;
  top: 0;
  left: 0;
  background: #292970;
  display: flex;
  flex-direction: column;
  align-items: stretch;
  justify-content: center;
  align-content: center;
}

.flex {
  min-height: 60pt;
}

@keyframes loading {
  0% {
    width: 50pt;
    height: 50pt;
    margin-top: 0;
  }
  25% {
    height: 4pt;
    margin-top: 23pt;
  }
  50% {
    width: 4pt;
  }
  75% {
    width: 50pt;
  }
  100% {
    width: 50pt;
    height: 50pt;
    margin-top: 0;
  }
}

.loader {
  width: 50pt;
  height: 50pt;
  border-radius: 100%;
  border: #6767fa 4pt solid;
  margin-left: auto;
  margin-right: auto;
  background-color: transparent;
  animation: loading 1s infinite;
}

.load-text {
  padding-top: 15px;
  text-align: center;
  font: 14pt "Helvetica Neue", Helvetica, Arial, sans-serif;
  color: lighten(#6767fa, 75%);
}