Interface explanation

This skill answers how something was built. /explain-interface how the gradient on example.com was built finds the layers producing that gradient and explains what each one contributes.

It explains rather than judges. There is no verdict, because how someone else built their interface is not a finding. Reviewing against a standard is interface-review and better-interface; exploring alternatives for your own is variant.

Scope to the question

Two questions. They share nothing but the evidence rules:

The question	What you produce	Method
How was this site built?	The frontend: framework and rendering strategy, styling system, component library, tokens, the type, spacing and color systems, motion, breakpoints, how fonts and images are served	read-the-system.md
How was this built?	The layer stack behind one effect, in paint order, with the technique on each layer	find-the-effect.md

Given a named thing, scope to it. A type scale and a token dump are not a longer answer to "how is the gradient built". They answer a question nobody asked. Pull in a neighbour only where the effect cannot be explained without it, and say why.

You can ask either question of a screenshot instead of a URL. That changes the answer in kind. See From a screenshot, it is a reconstruction.