I sometimes browse cohost on my secondary vertical monitor as it lets media render larger and more text fits on each line. However, I can't have the window be fullscreened (or wider than around 85% of my 1200x1920 monitor) or it enables the standard layout intended for widescreen, which causes 2/3 of the screen to become dead space and makes posts much smaller than normal. I'd appreciate if extremely tall and not-particularly-wide(-relatively) windows used the same mobile layout as a 1025px wide window.
Examples attached below showing an art post on a squished window (1025px wide, the maximum the mobile layout will render on) and a fullscreen window (1200px wide).
Oops, edited the post some more after doing the captcha and I didn't realize captcha timeouts remove images.
FWIW, you can easily mitigate this by holding down ctrl and scrolling up with the mouse wheel a bit. this adjusts the zoom for a single website, and cohost does seem to switch to the mobile layout after a certain point.
i use this all the time on firefox, and i personally like to pair it with the "zoom controls" tool from the toolbar customization menu. it's very handy :)