Grid won't take up 100% of container width

Hi all,

I created a 4x4 grid, nested in a div (set to max-width 1050px), which is nested in a container. For some reason, the grid isn’t taking up 100% of the div’s width.

I’m sure the reason lies in my misunderstanding of how grids and grid children work.

Here’s my site (note: the grid is toward the bottom, just above the footer).

Thanks!

The grid parent has 5% left and right padding.