Rated 5 out of 5 stars

ruma Firefox okisanel 9719e5 pa June 12, 2022 ·

Since my first review, the creator gave me a helping hand and now it works
You have to go into:
Preferences - General - Language&Appearance - Colors
and set the override to 'never' in the drop down menu "Override the colours....."

This review is for a previous version of the add-on (6.1.0).  This user has a previous review of this add-on.