Adding borders in table styles

Hi folks, I have a table style I've created that has green bands and suchlike on the rows (see below).

So we have pale green rows alternating with white rows, each separated by a darker green border.

I'd also like add to pale grey border to highlight the columns, but not sure if you can do this (within the table style itself).

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Any help gratefully received!

PS While I'm at it, is there any way to alter the headers in the table style to give them a little more "padding" above and below?