Semantic-UI is probably the only Modern UI that does not offer Responsive Navigation Bar. I created the NPM package: dna-responsive-nav to fix this limitation. If you are using Semantic-UI-React, then you may give it a try.
In this article, I show you how I implemented the tags function using remote data. The frontend is done by the Semantic UI Dropdown component and the backend is implemented using FeathersJS with Mongodb.
Semantic UI's table component is not quite mobile-friendly even with the stackable option. Actually, there is no standard way to make a stable responsive. A horizontal scrollable table is often being used, but if you like a stackable way, and with a table header as a label on each row, then in this article, I will show you how to do it using existing Semantic UI's table component with some small changes.