message: Allow custom dark background
diff: @mixin semi-bold {
  font-weight: 600;
  }
  -@mixin default-background-color {
  +@mixin default-background-color($dark-color: #333) {
  background-color: #fff;
  body.dark & {
  - background-color: #333;
  + background-color: $dark-color;
  }
  }
  @mixin absolute-h-center($position: absolute) {
  