tabler/scss/mixins/_mixins.scss

@mixin subheader($include-color: true) {
  font-size: $h6-font-size;
  font-weight: $font-weight-bold;
  text-transform: uppercase;
  letter-spacing: .04em;

  @if ($include-color) {
    color: $text-muted;
  }
}

@mixin scrollbar($is-dark: false) {
  &::-webkit-scrollbar {
    width: 6px;
    height: 6px;
    transition: .3s background;
  }

  &::-webkit-scrollbar-thumb {
    border-radius: 5px;

    @if ($is-dark) {
      background: transparent;
    } @else {
      background: $gray-400;
    }
  }

  &:hover::-webkit-scrollbar-thumb {
    background: $gray-500;

    @if ($is-dark) {
      background: mix(#fff, $dark, 20%);
    } @else {
      background: $gray-500;
    }
  }
}

@mixin dark {
  .bg-dark &,
  .theme-dark & {
    @content;
  }
}