Browsers need color-scheme: dark on the document (html/body) to properly
style native form controls like select dropdown options. Previously,
color-scheme was only set on select elements themselves, which didn't
propagate to the OS-rendered dropdown options.
Added bodykw to fast_app() to set color-scheme: dark on body element.
This tells the browser the entire page prefers dark mode, and native
controls use dark system colors.
Includes E2E tests verifying body and select elements have dark
color-scheme.
Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
Petru Paler
282ad9b4d7