@mixin hover-border($pseudo: before, $width: 5px, $background-color: $hover-border-background-color) {
  $modifier: left;
  @if $pseudo == after { $modifier: right; }
  &:#{$pseudo} {
    @include transition(all .3s ease);
    #{$modifier}: 0;
    background-color: $background-color;
    bottom: 0;
    content: '';
    position: absolute;
    top: 0;
    width: $width;
    z-index: 100;
  }
}