Be careful about Stylish - since it was sold, it stirred a lot of the community by dropping the original ideals and including tracking software. The change of

Be careful about Stylish - since it was sold, it stirred a lot of the community by dropping the original ideals and including tracking software. The change of hands happened after the last Firefox version update, so it should be safe for the time being. If you follow why the Stylus extension was made (port from Chrome's Stylish), you can find more explanations.