A subgrid item has its own `gap` set to a value different from the parent grid's `gap`. Which gap actually applies between the subgrid's tracks, and how does the parent's gap factor into the subgrid's track positions?
.parent { display: grid; gap: 40px; grid-template-columns: repeat(4, 1fr); }
.sub { grid-column: 1 / 5; display: grid; grid-template-columns: subgrid; gap: 8px; }