Very nice addon, quick and easy to use even on the webextension pages such as firefox pages (since Firefox 57 ...)

Please, dont forget to say what translation service it uses ... Is it Google ?

Moreover, I love Linguee for "expressions" ... Linguee gives "translations in context" which is of great help ...
So would it be possible to add (or create) the possibility to use Linguee in your addon ?

Last thing ... a choice for the background color of the popup would be a nice feature for people with poor eyes ... like me.

Nice job anyway !
Thanks