Two causes. The activity's window was a Light platform theme with no
values-night, so the bare window was white whatever theme was picked. And on
the category and poem screens Load sits outside the Scaffold, so while a page
was loading nothing painted a background and that white window showed through.
The window is now painted from the chosen theme before the first frame, and
kept in step when the theme changes, which a static XML theme could not do for
sepia or OLED. Load paints its own loading and error states too.
Android 12+ draws its splash before any app code runs, so that one can only
follow the system light/dark setting; picking sepia or OLED on a light-mode
phone still shows a light splash for a frame.
Verified on an API 36 emulator under the OLED theme: the loading screen is now
true black with the themed spinner.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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