When theme is "system", ThemeProvider removed the data-mode attribute
from <html>, expecting color-scheme: light dark to handle dark mode.
However, Tailwind dark: utilities are mapped to [data-mode="dark"] via
@custom-variant and do not respond to color-scheme, so dark mode never
activated for system preference users.
Decouple DOM synchronization from the theme preference by syncing
data-mode with resolvedTheme instead. This ensures data-mode is always
set to "light" or "dark" regardless of whether the user chose explicitly
or follows system preference.
Fixes#96
Co-authored-by: Matt Kane <mkane@cloudflare.com>
73b71b4e59