This is the same 8/4 split as the left-sidebar page with the columns swapped: the reading area takes the left edge and the rail sits to the right. Readers enter a page at the top-left, so the article wins the first glance and the rail becomes a quiet second column — the arrangement most blogs and news sites settle on.

It's the natural home for complementary material: author bios, related links, calls to action, a signup form. Nothing in the rail is required to understand the page; everything in it rewards the reader who finishes and wants somewhere to go next.

Put the destination in the rail, not the journey — the article is the journey.

On phones the columns stack in source order, which here already puts the article first — no order utilities needed. That's the practical difference from the left-sidebar page: this layout is simpler in the markup, while the left-rail version spends two utility classes to get the same mobile behavior.

If your rail is mostly navigation, consider the left-sidebar arrangement instead; if it's mostly “what next” material, keep it here on the right. When you genuinely need both, the two-sidebar layout gives each job its own column.