Getting Block Showing In White into Header Image

I have created this effect at https://www.paintwithray.co.uk/gallery/. The issue I am having is that the white block which contains the text ” All of these paintings were created in our studio and are for sale. The prices quoted do not include framing but do include postage.” I want to reproduce the same effect on a development site see http://www.icreate-websites.co.uk/ homepage.

I have made the same setting for the Heading Text ie ” Welcome to Salad Skills” but want the same border to run into the banner with a white background similar to the effect https://www.paintwithray.co.uk/gallery/ but running into the rotating banner. However I cant get a white background for the header even though I have set in the edit column section as in the paint with ray website.

I have also included a link of another website to show what an example of the effect we are trying to achieve:http://www.doctorkilpatrickandpartners.co.uk/

Hope this all makes sense and that you can help

Pete