chamilo-lms2/assets/css/scss/_loader.scss

// ---------------------------------------------------------
// SPINNER LOAD
// ---------------------------------------------------------

#loader {
  transition: all 0.3s ease-in-out;
  opacity: 1;
  display: initial;
}

#loader.fadeOut {
  opacity: 0;
  display: none;
}

.spinner {
  width: 40px;
  height: 40px;
  position: absolute;
  top: calc(50% - 20px);
  left: calc(50% - 20px);
  background-color: #333;
  border-radius: 100%;
  -webkit-animation: sk-scaleout 1.0s infinite ease-in-out;
  animation: sk-scaleout 1.0s infinite ease-in-out;
}

@-webkit-keyframes sk-scaleout {
  0% { -webkit-transform: scale(0) }
  100% {
    -webkit-transform: scale(1.0);
    opacity: 0;
  }
}

@keyframes sk-scaleout {
  0% {
    -webkit-transform: scale(0);
    transform: scale(0);
  } 100% {
      -webkit-transform: scale(1.0);
      transform: scale(1.0);
      opacity: 0;
    }
}