Side note on the design that's sort of a personal opinion, I absolutely despise websites that immediately shove a non-closable modal forcing me to sign up before even seeing anything checking things thoroughly. The idea of having something in the background with modal on top that's not closable just to entice/attract me as a user is a MAJOR signal that some sort of a shady data-selling something is going on in you background, aka service doesn't care-about/respect actual users but just trying to increase the number of signups/gather-more-data. Even if I was ok with signing up with Twitter, this sort of dark pattern is an instant close-tab for me, I wouldn't even bother removing the overlay crap with ublock.