Q1: How can I tell when design is overwritten locally?
A1: When you've overwritten design locally on your website, it's indicated in the design overlay by a grey dot next to the element that's changed. By hovering the grey dot an arrow will appear, click on this arrow to go back to following global design.
Q2: Has the connection between global and local design changed in the New Interface?
A2: No, the connection between the two design types haven't changed in the New Interface. The only thing that has changed is that you can access global design for a specific module directly from the module. You do this by opening the design section for the module and click on the link "global design" which will forward you to global design for that module type.
Q3: Why can't I style the global design of the pre-defined rows in the same way as module?
A3: Pre-defined rows are styled by all your global design components. You can't define or change the pre-defined row library but when adding it to your website it automatically uses both global design and data.