Closing a set of contour lines and filling with contour gradient

Hi, I have extracted a set of contour lines and have them set to a gradient, which I am then baking into rhino with colour for use in illustrator/ photoshop (pic attached).

What I can’t work out how to do (stepping back into gh after a few years away…!) is close the contours and then fill them (with a hatch I guess?) that is the same colour and the bounding line. If anyone has any ideas I’d massively appreciate it! Thanks, Rob

Thanks, am I posting this question incorrectly? here is the gh file.
Colorgradient createlayer bake.gh (2.7 MB)