I am looking for the exact same solution just for the .blog-masonry gallery to make it show 2 columns side by side on mobile.
I did try to use your code @tuanphan for the masonry and exchanged the elements with those of blog-masonry / blog-item etc., but unfortunately it wouldn't work... (see screenshot attached).
Do you maybe have a solution for this use-case too?
This is the page: https://caterpillar-elk-gzg2.squarespace.com/family-and-friends
PW: standout