move nested mixin dtStyle that it isn't nested in the table mixin
to fix build error:
Error: bower_components/sass-common/dist/sass/_mixins/structure.scss
staticcontent_1 | Error: Mixins may not be defined within control directives or other mixins.
staticcontent_1 | on line 307 of bower_components/sass-common/dist/sass/_mixins/structure.scss
staticcontent_1 | >> @mixin dtStyle {