Hi, to change the font size in the menu bar, just follow the step:

1.) Open Firefox, type about:config in the address bar and enter it. 2.) After that, click Accept the Risk and continue 3.) Type devp in the filter box 4.) Choose and double click layout.css.devPixelsPerPx to edit the font size in the menu bar. 5.) Change its value to 1.0 above such as 1.5 or 2.0 and click OK.

Don't choose a value below 1.0 or about 4.0 or you may find it difficult to get back to a viewable Firefox!

Refer Website: https://support.mozilla.org/en-US/questions/1239467

I know that. It makes everything bigger. I only want bigger font, thank you.

same problem here , so annoying eye pain, why there was no font size and letter box size setting

same problem here , so annoying eye pain, why there was no font size and letter box size setting

Currently, there's no built-in method for changing just the font sizes in the user interface. Also, add-ons don't have privileges to do it.

That leaves unofficial/unsupported workarounds from the community. In particular, Firefox can be set to look for a style file at startup (userChrome.css). I have a website with more information about this option, but I don't have a specific font size rule to apply. For that, the Reddit community r/FirefoxCSS would be a good source:

• https://www.userchrome.org/
• https://www.reddit.com/r/FirefoxCSS/