Add a center line to the predefined grid

[RyanBohan]

I am working with 4 cards arranged in a grid pattern.  How do I get rid of the center gap? 

It seems there is a predefined background grid the cards are snapping too, however there is no way to adjust the cards to be flush with each other.  Or add a line in the center to use as a guide.  This project is being designed for mobile, so the 10ish pixel gap is space I would like to use

[RyanBohan · Accepted solution]

Had the pleasure of getting the solution from Jianxia herself and wanted to share with everyone.  Set the Gap to 0 px on your block / row.  Huge thank you Jianxia