Please see this image ---> [https://en.wikisource.org/wiki/File:Page_links.png]
Specifically, en.wikisource main namespace page link below the the header need adjustment because it runs into the header when displayed alongside the left margin. When it's toggled for display alongside the text, it is positioned lower, and displays OK. This occurs on any screen size, in any OS, but only in Firefox. Cannot be replicated in Chrome/Chromium.