Editing mobile version of slider

This is a website I am working on : realtimeyield.com

As you can see, in the mobile version you cant see the slider images when there is overlay on it. However, when I remove the overlay, I can see the slider images.

When I responsively edit the slider on mobile, it edits it on desktop as well. Is there a way that I can edit it just on mobile? So I can have no overlay text/image on mobile?

thank you in advance