Anti-Flashbang av FrostyByte

Anti-Flashbang paints a dark background at the very first moment of page
load, preventing the white flash between navigations.

Unlike Dark Reader, it never touches individual elements. The curtain is a
single CSS rule at user-stylesheet origin - no !important. When the page's
own stylesheet loads, it naturally overrides the curtain via cascade
ordering. No removal logic, no DOM mutation, no broken pages.

v1.2: Per-site exclusions
Sites where the dark background leaks through can be disabled from the
popup. Uncheck "Enable on this site" - the curtain is never injected on that
domain or any of its subdomains. Excluding github.com covers
gist.github.com, docs.github.com, and so on. Already-open tabs pick up
exclusions immediately without reloading.

Toggle on/off from the toolbar icon. No network calls. No telemetry.
No remote code. Just cascade physics.