On a website I'm creating, I have pages that are really short, and so can fit on one screen. I also have pages that are long, so there needs to be a scrollbar. My current styling works off of percentages, which means that on pages with a scrollbar, there is a visible shift as the central block moves to the left when you move from a page with less text to more text (due to the sudden appearance of a scrollbar reducing the width I have to work with).
I'm debating solving this by just forcing the scrollbar to always be on, even when the page is small enough to not need one. This would stop the main block jumping around, but I'm worried that (especially on smaller screens) it reduces the page size and could be annoying to users.
So, my question, which is the lesser of two evils? Forcing a scrollbar to always exist or having a central block that jumps as you navigate pages?