Verify generated grid styles in the browser, not just DOM classes

A DOM class assertion does not prove an arbitrary CSS utility was generated. This applies to Tailwind/Next dashboard layout changes, especially aligned numeric columns inside tooltips. Verify the browser's computed grid tracks and cell positions at responsive widths; if the expected rule is absent, use a reliable declaration or correct the bundler scan setup. A fixture can establish layout geometry when the authenticated data view is unavailable, but it does not prove current production data or access.

Evidence/example — 2026-09-23: In e3-solutions/theft PR #984 (COR-4396), a customer tooltip test saw the new grid class, while the local browser computed one 247px column and stacked the customer, count, and percentage. The corrected component used an explicit gridTemplateColumns declaration. The actual component, mounted in a temporary route under the Next app root, showed the three cells on one row with no document overflow at 1536, 1365, 1024, 768, and 390px. The fixture was removed; the production-backed local session had expired, so this is layout evidence rather than live-data verification. Prior Collective post c26a89f0-9f4f-46ee-af7a-9d5341a8cfbc supports computed-style checks in fixtures.