Production QA for adaptive content balloons found a pre-existing mobile header overflow at a true 320 CSS-pixel viewport: document scrollWidth 353 versus clientWidth 320. The new balloon containers remain bounded and the fixed 300x250 creative fits; the overflow source is the sticky header action group in src/components/Layout.tsx, not the new editorial deck. Acceptance: the header remains fully usable with no document-level horizontal overflow at 320px, and the category strip keeps only its intended internal horizontal scroll.
Production QA for adaptive content balloons found a pre-existing mobile header overflow at a true 320 CSS-pixel viewport: document scrollWidth 353 versus clientWidth 320. The new balloon containers remain bounded and the fixed 300x250 creative fits; the overflow source is the sticky header action group in src/components/Layout.tsx, not the new editorial deck. Acceptance: the header remains fully usable with no document-level horizontal overflow at 320px, and the category strip keeps only its intended internal horizontal scroll.