How to target only webview rendering with CSS?

This particular page displays correctly on desktop and mobile Firefox browsers, Mac and iOS browsers, Edge, Chrome, and Chromium.

But when it's seen through web view—that is, from a link on the Android Facebook app or even the actual Android app, Duck Duck Go—one of the font sizes is bigger and extends beyond its container div, obstructing the view.

Visit Here for more information on solving problems: Prodigit

After ten years of front-end development, I haven't yet looked at web view customizations.

How can I use CSS (or JavaScript if necessary) to target web view rendering?