The theme you are using is trying to load jQuery over HTTP, not HTTP.
When running on HTTPS, all content loaded over HTTP is blocked by browser for security reasons, as you can see in Web Inspector too.
RapidCart Pro and all other plugins and stacks requiring jQuery won’t work.
You need to change jQuery URL from
http://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js
to
https://ajax.googleapis.com/ajax/libs/jquery/1.6/jquery.min.js
if you can.
Otherwise you need to contact the theme developer asking to fix it.