JAST supply a simple way to let your site interactive with the visitor. It's easy to use, but can still do complicate survey questionnaires.
This my happen when content of public.css dosn't merge to style.css of current theme. If use @import to merge the CSS, pay attention to the single quotes which surrounding thr url of public.css.
You can set Survey post type slug at Settings -> Survey.
After you change the permalink structure, you need to re-active the plugin to flush the rewrite rule.