The homepage section of my dev site had 10px added to the right and left margin on the 1/3 column. I was able to inspect the element and find it assigned to this class:
.x-column.x-sm.x-1-3
However, I cannot locate this CSS anywhere. (I’ve searched the page CSS, theme options, Editor, Customizer — the latter two have no CSS). The margin only appears to apply to the homepage as I created a test page with the layout and that worked just fine.
I was able to apply a right and left margin of 0px under theme options, which corrected the display. However, I’m really interested to know where this was applied so that I can correct the source instead of my roundabout fix.
Thank you!