3_columns — main column (centre)
colPos 0, span 6 → 480px, order: 2 so it sits in the middle.
Three columns means two gutters, so --section-gaps: 2 and each column gives up proportionally more: 480 + 240 + 240 = 960, plus 2 × 60 = 1080.
First secondary column (renders left)
colPos 1, span 3 → 240px. Ordered first by .maincontent-wrap + .subcontent-wrap.
Second secondary column (renders right)
colPos 2, span 3 → 240px.