whitenAtBottom property
When true (default), the bar lifts its whitening toward whitenAtBottomTarget as the scrolled content nears the bottom of the page, so a light page stays readable through the bar. Light-mode only; set false to opt out.
Inert unless a scrollController is provided (the bar needs a scroll position to watch), so the defaults change nothing for existing callers.
Implementation
final bool whitenAtBottom;