For the past 5 or 6 major versions of Firefox, in some websites, sometimes the fonts used are rendered too thin, making it difficult to read. It's inconsistent though, it affects some websites but others not, a website may be affected today but not tomorrow, hitting ctrl+f5 several times or closing and reopening the browser a couple times, sometimes fix it, sometimes not. Looking at the font inspector, I couldn't find a specific font family that causes it, seems to be random too. Font settings are at the default. The source of the font file seems not to matter as well, it can be Google fonts, local fonts, the website server itself, even when developing locally... it's the same. Now in Firefox 103 none of the "tricks" I mentioned before are capable of fixing the problem when it happens to a particular website. I've seen a lot of questions in this forum about the same problem but nothing helps. In the attached screenshots you can see the difference between how it looks with and without the issue.