Where does UI end and just content and design begin?

Question

Design

Where does UI end and just content and design begin? For example, on the page, among other things, there are three boxes with a brief description of services and "more" buttons. Will these dice be considered user interface?

Answer 1

An interface is everything you use to interact with a system. There is no boundary between content and interface, since content is part of the interface. In particular, it is a means of information output. Buttons, switches, checkboxes, etc. - means of input.
In a broad sense, any web designer is a ui-designer, since when creating a design, you develop an interface (you need to understand, of course, that a designer is a constructor, not a graphic designer). In the real world, it would be wrong for any web designer to call himself a UI designer, since the development of the interface must comply with certain principles, and not just the developer's fantasies.
Everything that you see on the screen is the interface (actually, outside of it too - the mouse, keyboard, but we will not delve into this topic), and the creation process is the design. In a narrow sense, design is also the purely visual and aesthetic result of such a process.

Answer 2

Yes.
The UI ends where the user's interaction with the interface ends.

Answer 3

Content is the content of the site for which it was actually created: photos and descriptions of goods in the store, videos in the online cinema.
Everything else is interface elements, that is, UI. They can have direct functionality (by themselves, buttons, menus, other elements that are associated with user actions, ranging from navigation to just viewing content) and design functionality (a beautiful background has no direct function other than to "please the eye" ).
And "design" is a very broad concept, meaning, literally, a set of decisions on the presentation and placement of content, controls and navigation, the design of all this.