Web layout with margins in Microsoft Word or LibreOffice Writer?

Question

In any word processor, is there any way to restrict the width of the web layout view to a comfortable width for reading and writing? I understand that you could simply make the GUI window narrower but I was hoping for a less distracting option.

Another way to achieve a similar affect would be to have "continuous pages" in page layout view but that question has already been asked here: How to make a continuous sheet in MS Word?. Note that hiding white space between pages is not a solution to this since elements (think images) may not lay between page boundaries which causes ugly gaps in the continuous text.

I get frustrated that word processors are so focused on page layout.