Create Responsive background imag Twenty Twelve

Hello One of my customers has a specific request. He wants a website based on the wordpress twenty twelve theme with a special cascading background image like the attached image of the cascading element in the decor of a television show. The cascading element should be recreated in Photoshop. Please make sure the colour and shading is the same as on the picture. (colour should be adjustable, based on customer needs) The cascading element should function as a Picture frame around the body element of twenty twelve theme The cascading element should be responsive (see attachment 2): For Laptop screens: Layer 2 and 3 are both 1 cm thick (but both should be adjustable based on customer needs) Layer 1 fills up the rest of the background For smaller screens (i.e. iphone): Only Layer 2 and 3 is visible (but should be easily adjustable) Layer 2 and 3 are both 0,5 cm thick (but both should be adjustable based on customer needs) If you have any questions, please let me know Kind regards, Jan