Hi,
Thank you, I have checked the site and found that if I click on Advanced Settings it will create a cookie named jpanesliders_template-sliders-7, and the site will die, if I clear this cookie value the site will work back up, therefore this is not problem of CSS Override.
This is really a weird issue and I still don't know how to fix it, however I see that there are some strange things in your template configuration page that some buttons are missing, so please reinstall it first to check if it could help fix the issue as well.
Thanks,