firefox: shuffle the files

firefox/README.md

@@ -1,6 +1,12 @@
 # Firefox
 
+## userChrome
+
 1. Set `toolkit.legacyUserProfileCustomizations.stylesheets` to `true` with `about:config`
 1. Locate profile with `about:profiles`
 1. Copy `firefox/userChrome.css` to `{Root Directory}/chrome/userChrome.css`
 1. Customize interface
+
+## userStyles
+
+Styles can be applied using the [CSS Override extension](https://github.com/swcolegrove/css-override-web-extension).