Content width narrows to 3cm on scrolling page

Hi all,

I’m on WordPress 4.9.8 running the Hueman Pro theme, and I’m facing issues with my blog posts.
All looks fine at one glance, but as soon as I scroll down, it narrows the content to a width of around 3cm. This renders the blog post almost unreadable and it looks horrible. This is a problem only with Mozilla and works fine on other browsers. I have tested it on the Windows and Linux platforms.

[ redundant link removed ]
Thanks in advance.

• This topic was modified 6 years, 3 months ago by rinugour.
• This topic was modified 6 years ago by Jan Dembowski.

The page I need help with: [log in to see the link]