I have used Semantic UI styling with NPM before and it works well with DataTables.
However, for another project I decided to take the "Download" approach and bundle the features that I want.
When executing the necessary scripts, I found that the length change menu is not getting the Semantic UI styles applied to it. The wrapping div is not present. I went back and downloaded the bundle a second time and still presented with the same problem.
See screenshot below.