discourse/app/assets/stylesheets/common/input_tip.scss

@keyframes slidein {
  0% {
    transform: translateX(0px);
  }
  50% {
    transform: translateX(5px);
  }
  100% {
    transform: translateX(0px);
  }
}

.popup-tip {
  @include form-item-sizing;
  position: absolute;
  z-index: z("composer", "dropdown") + 1;
  cursor: pointer;
  animation: 0.15s slidein 3;

  &.bad {
    background: var(--danger-medium);
    color: white;
    box-shadow: shadow("dropdown");
  }
  &.hide,
  &.good {
    display: none;
  }
  .d-icon {
    color: var(--primary);
    opacity: 0.5;
    font-size: var(--font-0);
    &:hover {
      opacity: 1;
    }
  }
}