For the XS preview, I tried to add the Galaxy fold (which already exists in its unfolded state.)
But in it’s folded state, it has a screen that measures 280px in width by 653px in height. Bootstrap Studio will not accept the number 280. If I type it in, it just defaults back to 320px.
There should be no limit on how narrow the custom screen width can be, especially with the advent of foldable phones and the likelihood that there will be future screen dimension we may need to accommodate on our websites, but the dimensions of which we cannot foresee until they’re released by the manufacturers.