[asiando]

The author is actually complaining about narrow viewports and not about portrait orientations, without even realizing it.

[madeofpalk]

Even then - when I set my resolution to the same 1080 × 1920 the author states, The Guardian still renders the "desktop" layout. The more compact layout from the doesn't kick in until 739px.

Maybe it's their font-scaling settings are getting in the way and changing the viewport resolution?