Layout - frontend or backend?

Question

Layout

I read in one article that the frontend is the visible part of the site that the user sees, and the backend is the part of the site that is not visible to the user, that is, "invisible". In this regard, the question arose, does the layout belong to the frontend or to the backend? After all, the user does not see the HTML code itself, but only what the browser will render based on the received code. Tell me please.

Answer 1

layout is UI