With Oneplus 9 + Chrome, font styling is different with page and footer. It has to be set 16px for footer and 15px for page content to get font size match in Oneplus.
When in the meantime in every other device shows as it should footer with bigger font than content.
sounds like an issue with that particular device, different phone manufacturers do odd things with their Android installs. Seems you’re not the only one:
The Theme simply outputs what you ‘effectively’ tell it to – it doesn’t know what device the site is being viewed on and therefore cannot remedy issues that are device related.