Appointments+ [app_login] not mobile responsive

my problem:

the [app_login] area of the Appointments+ plugin is not mobile responsive - can someone please help?

here's the site to review on iPhone:

once you book a time, the name, email address & phone fields fall off the page - i want it to be responsive like the rest.

i tried removing the tables here and no luck:

please help - thx very much in advance!