Hi   !

You're right;   zoom doesn't work,   but this will:
3-bar menu > Options > Content > Fonts and colors
Click on   'advanced'   (on the right side)
I have mine set :   proportional :   16,   and   Monospace :   13
But that's a personal choice, of course.
Good luck   !

Sorry, but what do you mean by "zoom does not work"? Do you mean on a particular website or page, or zoom does not work for you on ANY web page ever?

What update did you install? If you're not sure, could you check your update history from this page, either:

• "3-bar" menu button > "?" button > Troubleshooting Information
• (menu bar) Help > Troubleshooting Information
• type or paste about:support in the address bar and press Enter

In the first table on the page, look for a "Show Update History" button. This should list each recent update so you can see what your immediately previous version was and what your current version is.

Oh, if you just updated to Firefox 47, do you use the NoSquint extension? It stopped working in Firefox 47 and no more updates will be issued. You can switch to a different one.

To remove NoSquint, open the Add-ons page using either:

• Ctrl+Shift+a (Mac: Command+Shift+a)
• "3-bar" menu button (or Tools menu) > Add-ons

In the left column, click Extensions. Then find NoSquint on the right side and Remove it. (If you're not confident, Disable it.)

Often a link will appear above at least one disabled extension to restart Firefox. You can complete your work on the tab and click one of the links as the last step.

Then you can install an alternate extension to set a new base font level. This one has some handy features: Zoom Page (includes "fit to window" feature).