The light inbox screenshot in the README was not light, and had not been
since it was first taken -- the pair showed the dark theme twice.
The app was never at fault: update() calls applyTheme() synchronously
and the CSS flips --bg to #f6f8fa as it should. The capture was.
Swapping the theme under setDeviceMetricsOverride produces a mixed
frame, the panes that re-rendered in the new theme and the rest of the
chrome still in the old one, while the DOM and computed styles insist
the whole page is light. Clicking the app's own toggle, setting the
attribute, pinning it against applyTheme with a MutationObserver,
installing that pin before the document loads, nudging the viewport and
forcing a full reflow all left the frame mixed.
Chrome launched at --window-size, with the emulation layer never
touched, renders it correctly. That is docs/screenshots-light.mjs, and
inbox-light.jpg is now genuinely light.
assertTheme() stays: without it the script wrote a dark screenshot under
a light caption and reported success, which is how this survived
unnoticed. The header says which shots are taken elsewhere and why.
jcoffey-dev
00868f053c
