hidden 'data' in 'area'

[neckva]

Hello
Thanks for the framework.
I would like to put a background image on an 'area'. Unfortunately, by doing this I'm deleting part of the 'data'. I suspect that the 'td:before' in the next column is hiding part of the data. I've tried changing the z-index, but it has no effect. Do you have any ideas?

thank