authelia/client-react/src/components/CircleLoader/CircleLoader.module.scss

$brand-success: #5cb85c;
$brand-failure: #d44141;
$loader-size: 4em;
$check-height: $loader-size/2;
$check-width: $check-height/2;
$check-left: ($loader-size/6 + $loader-size/25);
$check-thickness: 3px;
$check-color: $brand-success;

$cross-height: $loader-size/2;
$cross-width: $check-height/10 - $check-height/12;
$cross-left: $loader-size/2;
$cross-top: $loader-size/4;

.circleLoader {
  border: 1px solid rgba(0, 0, 0, 0.2);
  border-left-color: $check-color;
  animation: loader-spin 1.2s infinite linear;
  position: relative;
  display: inline-block;
  vertical-align: top;
  border-radius: 50%;
  width: $loader-size;
  height: $loader-size;
}

.loadComplete {
  -webkit-animation: none;
  animation: none;
  transition: border 500ms ease-out;
  &.success {
    border-color: $brand-success;
  }
  &.failure {
    border-color: $brand-failure;
  }
}

.checkmark {
  display: none;

  &.show {
    display: inline;
  }
  
  &.draw:after {
    animation-duration: 800ms;
    animation-timing-function: ease;
    animation-name: checkmark;
    transform: scaleX(-1) rotate(135deg);
  }
  
  &:after {
    opacity: 1;
    height: $check-height;
    width: $check-width;
    transform-origin: left top;
    border-right: $check-thickness solid $check-color;
    border-top: $check-thickness solid $check-color;
    content: '';
    left: $check-left;
    top: $check-height;
    position: absolute;
  }
}

.cross {
  display: none;

  &.show {
    display: inline;
  }

  &.draw:after, &.draw:before {
    animation-duration: 300ms;
    animation-timing-function: ease;
    animation-name: cross;
  }

  &:before, &:after {
    position: absolute;
    left: $cross-left;
    top: $cross-top;
    content: '';
    height: $cross-height;
    width: $cross-width;
    background-color: $brand-failure;
  }

  &:before {
    transform: rotate(45deg);
  }

  &:after {
    transform: rotate(-45deg);
  }
}

@keyframes loader-spin {
  0% {
    transform: rotate(0deg);
  }
  100% {
    transform: rotate(360deg);
  }
}

@keyframes checkmark {
  0% {
    height: 0;
    width: 0;
    opacity: 1;
  }
  20% {
    height: 0;
    width: $check-width;
    opacity: 1;
  }
  40% {
    height: $check-height;
    width: $check-width;
    opacity: 1;
  }
  100% {
    height: $check-height;
    width: $check-width;
    opacity: 1;
  }
}

@keyframes cross {
  0% {
    width: 0;
    height: 0;
  }
  20% {
    height: 0;
    width: $cross-width;
  }
  40% {
    height: $cross-height;
    width: $cross-width;
  }
  100% {
    width: $cross-width;
    height: $cross-height;
  }
}