Shadow only left & right - not top & bottom

Hello all,

Is there any Trick I don’t find, how to have a shadow only on the left and right side of rows, but NOT on top and bottom?

I have a fixed content width of 1200px over all rows and I want to have a shafows on left and right, so that the content is “flying” over the background image.

When I use the normal shadow feature, I also have shadows on the top and bottom of a row.