- Go to
about:config
and settoolkit.legacyUserProfileCustomizations.stylesheets
totrue
. - Go to
about:profiles
and underProfile:default
, click onOpen Directory
next toRoot Directory
. - In the file browser that just opened, go to the
chrome
directory (or make it if it doesn't exist). - Inside the
chrome
directory, create a file calleduserContent.css
with the following code (#383c4a
can be changed to the hex color you prefer):
@-moz-document
url("about:blank"),
url("about:home"),