Rated 5 out of 5 stars

I like the addon very much. I think it will be better to remember the font size settings for a certain site. Please consider adding this feature. Thanks!

This review is for a previous version of the add-on (4.4). 

I will look into adding domain-dependent settings. Until recently, the minimum font size was an application-global setting. The multi-process versions of Firefox might allow for a domain-dependent implementation.