firefox-theming

Installation
SKILL.md

Firefox Theming

Source of truth

Firefox ships CSS inside omni.ja (a zip file). Always extract and read source files before writing or auditing userChrome rules.

Extract source

OMNI=$(ls /nix/store/*firefox-unwrapped*/lib/firefox/browser/omni.ja 2>/dev/null | head -1)
OMNI_TK=$(ls /nix/store/*firefox-unwrapped*/lib/firefox/omni.ja 2>/dev/null | head -1)
DEST=/tmp/ff-omni

mkdir -p "$DEST" && cd "$DEST"

# CSS
unzip -o "$OMNI" "chrome/browser/skin/classic/browser/*.css" "chrome/browser/skin/classic/browser/**/*.css" 2>/dev/null
unzip -o "$OMNI_TK" "chrome/toolkit/skin/classic/global/*.css" "chrome/toolkit/skin/classic/global/**/*.css" 2>/dev/null
Related skills
Installs
10
Repository
knoopx/pi
GitHub Stars
47
First Seen
Mar 1, 2026