.pre-loading {
  display: flex;
  justify-content: center;
  align-items: center;
  height: 100vh;
  width: 100vw;
  overflow: hidden;
  background-color: #0078D7;
}

/* Theme color -- gray */
.pre-loading--gray {
  background-color: #fff;
}

.pre-loading--gray .pre-loading__text {
  color: #aaa;
  text-shadow: 1px 1px 1px #fff;
}

.pre-loading--gray .pre-loading__box {
  border-color: #666;
  box-shadow: 0 0 5px rgba(0, 0, 0, .2);
}
.pre-loading--gray .pre-loading__box-inner {
  background-color: #666;
}

.pre-loading-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.pre-loading__text {
  font-size: 16px;
  margin-top: 3rem;
  color: #eee;
  text-shadow: 2px 2px 1px #333;
}

.pre-loading__loader{
  display: inline-block;
  width: 2rem;
  height: 2rem;
  vertical-align: text-bottom;
  border: .25em solid currentColor;
  border-right-color: transparent;
  border-radius: 50%;
  animation: spinner-border .75s linear infinite;
}

.pre-loading__box {
  display: inline-block;
  width: 48px;
  height: 48px;
  position: relative;
  border: 6px solid white;
  animation: loader-box 2s infinite ease;
  border-radius: 2px;
  box-shadow: 0 0 8px rgba(0, 0, 0, .5);
}

.pre-loading__box-inner {
  vertical-align: top;
  display: inline-block;
  width: 100%;
  background-color: #fff;
  animation: loader-box-inner 2s infinite ease-in;
}

@keyframes spinner-border {
  to {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);
  }
}

@keyframes loader-box {
  0% {
    -webkit-transform: rotate(0deg);
    transform: rotate(0deg);
  }
  
  25% {
    -webkit-transform: rotate(180deg);
    transform: rotate(180deg);
  }
  
  50% {
    -webkit-transform: rotate(180deg);
    transform: rotate(180deg);
  }
  
  75% {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);
  }
  
  100% {
    -webkit-transform: rotate(360deg);
    transform: rotate(360deg);
  }
}

@keyframes loader-box-inner {
  0% {
    height: 0%;
  }
  
  25% {
    height: 0%;
  }
  
  50% {
    height: 100%;
  }
  
  75% {
    height: 100%;
  }
  
  100% {
    height: 0%;
  }
}