[FR]: Keep the articles viewer size in vertical and horizontal layouts separately

[akinokonomi]

Brief description of the feature request

Hi.

Since some articles look better in horizontal layout and some in vertical, I frequently switch between them.
However, when I do that, the relative width/height remains constant. That is, resizing the articles viewport to
~30% of a window would make it stay ~30% in both vertical and horizontal layouts. Due to this, I always resize it after switching the layout.

For example me, in horizontal layout I like the viewport to take half a width of the window, while in vertical I prefer it being much less.

Thank you for your work.

[martinrotter]

Fixed with 2f39114

Test and let know if it works.

[akinokonomi]

@martinrotter, It works great! Thanks.