.preloader{
  display: flex;
  justify-content: center;
  align-items: center;
  background: rgba(0,0,0,0.3);
  z-index: 100000;
  width: 100%;
  height: 100%;
  position: fixed;
  top: 0;
  left: 0;
  flex-direction: column;
  color: #FFF;
}

.preloader .spinner{
  border-radius: 50%;
  border-top: 6px solid #2979FF;
  border-left: 6px solid #2979FF;
  border-right: 6px solid #2979FF;
  border-bottom: 6px solid #FFF;
  height: 50px;
  width: 50px;
  animation-name: preloader;
  animation-duration: 1s;
  animation-iteration-count: infinite;
  animation-timing-function: linear;
  margin: 10px;
}

@keyframes preloader{
  0% { transform: rotate(0deg); }
  100% { transform: rotate(360deg); }
}