Hi again, Ocelot
Thanks for your feedback.
We have got access to your website, then fixed the issue:
1> We fixed the issue of Testimonial Slider, it works fine now.
2> We helped you to add 'WP_MEMORY_LIMIT', '256M' ); in wp-config.php file. This action will help you can Save&General CSS normally.
3> Fixed the color of the menu.
In addition, we found that you are using many Custom CSS segments to Theme Options, we think you should add CSS segment on style.css of your Child Theme. It will help you can run the Dashboard clearly.
Please check, then feedback us soon.
Best Regards,
Tracy