I struggle to come up with a distinction between the two, with respect to the original post. The design work that goes into programming is largely irrespective of the problem. In fact, if you stick to common design methodologies you often won't even see a significant difference between "front end" and "back end" work – and I might even suggest the line is completely arbitrary.

I'm thinking about things like animations & css work. That is almost entirely aesthetic, and thus more like architecture. Even when I'm writing the entire app, I draw a pretty clear distinction between 'front-end'/UI and 'back-end' type work.

That seems more like paint to me, which is certainly important in its own right, but not the core focus of an architect, or what I think the parent was trying to convey. The architect is more concerned with structure and conveying feeling to other people – which is other programmers in the case of code. Attention to aesthetics is important, but those aesthetics are more like how to appropriately use whitespace to evoke a sense of beauty when the next person catches a glimpse of your work in a text editor, to ensure that the reader understand that "a door is a door and not a window", things like that.