A page that never adapts to the viewport

The phone is not the edge case. It is the most common screen a page is read on, and a layout composed for a wide screen and left alone arrives there as a horizontal scroll, a nav whose last links are off the edge, and three cards crushed to a third of 375px each. This is decided for the whole project, not per file, because the grid and the query that collapses it routinely live in different stylesheets. It only reports what is laid out side by side: a single column of text with a max-width works on a phone with no breakpoint at all, and is not a finding. Two things do not count as adapting, and both are traps. A prefers-reduced-motion query is about the user, not the width — and L-04 asks every page for one, so counting it would let a fixed-width page pass by following the self-check. And shrinking is not adapting: the same three columns at a smaller size are still three columns. That second failure is critique's to judge on a render; this rule catches only the page that never responds at all.