Rated 5 out of 5 stars

by SoCu on Oct. 14, 2017 ·

Thanks for answering,

Do you have in your plans to make it to work with FF 57?

This review is for a previous version of the add-on (0.5.5).  This user has a previous review of this add-on.

by ChoGGi (Developer) on Oct. 15, 2017 ·

If the WebExtensions API doesn't support it, nothing I can do.

As long as FF keeps support for UserChrome.css, you can still manually add the CSS (just stick the mosaic in the same folder as userchrome.css).