How to remove the theme applied background?

I have changed both the form background and the layout background to something other than the denim, but even after saving it, the denim is still the background.  I do not like the denim and it will not go away.

Hi,

You have a theme applied to your jotform, which is still being active.

In order to just remove the background and not make any changes to the rest of the fields I would recommend that you inject this CSS code:

.supernova > body {
    background: none repeat scroll 0 0 transparent;
}

Please check this guide to see how to inject the codes to your jotform.

Best Regards,
Ben