message: style(content-section): fixing theme error on storybook
diff: @import '../../../../../../styles/scss/patterns/sub-patterns/content-section/content-section';
  +@mixin themed-items {
  + color: $text-01;
  + background: $ui-01;
  +}
  +
  .#{$prefix}--content-section-story .#{$prefix}--content-section__children {
  height: carbon--mini-units(60);
  - background-color: #f4f4f4;
  padding: $carbon--spacing-05;
  + @include themed-items;
  +}
  +
  +.#{$prefix}--content-section--g10 .#{$prefix}--content-section__children {
  + @include carbon--theme($carbon--theme--g10) {
  + @include themed-items;
  + }
  +}
  +
  +.#{$prefix}--content-section--g90 .#{$prefix}--content-section__children {
  + @include carbon--theme($carbon--theme--g90) {
  + @include themed-items;
  + }
  +}
  +
  +.#{$prefix}--content-section--g100 .#{$prefix}--content-section__children {
  + @include carbon--theme($carbon--theme--g100) {
  + @include themed-items;
  + }
  }
  