Yikes. I get not supporting mobile for now, but what about people who like to use little browser windows like me? Doesn't seem to be responsive at all.
I understand your problem. Apparently, our front-end dev isn't available on weekdays, so we are discussing it and trying to optimize the frontend. Thank you for your feedback.
I have always assumed that people like to use at least most of their screen's real estate if not all - what is your reason for liking narrow windows (especially considering that I think even nowadays on most of the web the experience would be degraded)
Multitasking. Watching videos, writing something up, having another website open, messaging, Skype, or anything else you can think of while browsing. Having two windows open side by side isn't abnormal and is one of the main reasons why window managers even exist instead of desktops using a mobile-like UI paradigm where you can only have one program on the screen at a time.
Counter question: why would you want something as one-dimensional as a website (especially the OP) taking up all of your screen real estate?
most people I see do this do it on multiple screens not multiple windows on one screen (or multiple tablet sized windows on one large screen, and most do it without making any screen as extremely narrow as the parent did.
However I suppose also that most is not all, and there must be some outliers who do it on a single laptop screen either from necessity or preference. I might find myself doing extremely narrow windows out of necessity but never preference, and then the extremely narrow windows would almost always be on something I was working on - as it is indeed in your case - and not to interact with someone else's site.
As a general rule then I would move between tabs or windows if I were reading documentation or help on a subject.
I tend not to read at the same time as programming, I might read, stop reading, and then program based on what I read, but not have two tools open and have my eyes continually hopping between them.