# M14-04G Status

status: done
task: Chromium responsive layout no-overlap/no-overflow matrix
updated: 2026-08-19 America/New_York
enablingTask: false
parityStateChange: false

## Scope

The Chromium layout gate now covers main-thread WebGL and OffscreenCanvas Worker viewports at
1440x900, 1280x720, 834x1112 and 390x844 with DPR 1 and 2. It checks root/body horizontal overflow,
layout-band containment, text overflow and app bounds. The mobile breakpoint moved to 900px so the
834px tablet layout hides the desktop menu before it can widen the document.

## Evidence

- `npm --prefix web run build` passed.
- `npm --prefix web run test:chromium-layout` passed: 16 real Chromium combinations (2 backends x
  2 DPR values x 4 viewports).
- Checker output: `chromium-layout-ok backends=main,offscreen viewports=4 dpr=1,2 results=16 execution=DISABLED next=M14-04H`.
- `npm --prefix web run typecheck` and `git diff --check` passed.

## Artifact Hashes

- parent manifest: `895b460477a8379594ee93043139b9521952638dbd6670b0205eab1896886455`
- checker: `b211b703309e22810c39f85e4801bc5f0690fa682e33cdcb85157bd28ea042c0`
- app: `92d01daecf3f39bc4ac214e4b651ec6feb687bbfbf58c4d3e602a314cdcc664c`
- CSS: `5961164f29e25b461c03201534fe56e32020633cac6c0970e149a58ba9f6e9fc`
- main viewport: `e8d97cb59fd4eca3789aeeb35221a70cf47ef048a5665383d809d0efc49f7119`
- offscreen viewport: `4a210ae247d0e29972096da6c206f3457c2238e6061c6eb622f0ce55c6bfd439`
- reference e2e: `f5de57f570880f823224ebdcddb2be4d59ec414a32641effdaa68dc1f4102f28`
- report: `65b1050217e2343e656d56c4d7893d13f36b5f07008288ea194a101dafbaa0e2`
- manifest: `a5a80cedd824cc4aac27bd2cec39e11560d4cf3207ab947a1abe19c8bb9e053f`

## Next Task

`M14-04H`: Chromium keyboard-only, accessible names/roles and focus restoration.

## Rollback

Remove the 900px breakpoint change, layout checker, report, manifest, package command and this status/task
entry; restore `M14-04F` as the queue tail.