[v56+] Type about:preferences#general<enter> in the address bar. Under fonts and colors, press the Advanced button. Scroll to the bottom, turn on Allow Web Sites To Choose Their Own.

Make sure you haven't enabled a High Contrast theme in the OS settings.

• We have seen reports that this can be caused by a problem with fonts like Roboto or Helvetica that

you have installed locally and that might be corrupted or are missing some variants. Also, make sure you allow pages to choose their own fonts and that you do not block remote (downloadable) fonts.

• https://support.mozilla.org/questions/1325619 Weird font on some website's

• If you use uBlock Origin make sure not to "block remote fonts".

Many site issues can be caused by corrupt cookies or cache.

Warning ! ! This will log you out of sites you're logged in to. You may also lose any settings for that website.

• Delete cookies to remove the information websites have stored on your computer {web link}

• How to clear the Firefox cache {web link}

If there is still a problem,

Start Firefox using Troubleshoot(Safe) Mode {web link}

A small dialog should appear. Click Start In Troubleshoot(Safe) Mode (not Refresh). Is the problem still there?

While you are in Troubleshoot(Safe) mode;

Try disabling graphics hardware acceleration in Firefox. Since this feature was added to Firefox it has gradually improved but there are still a few glitches.

How to disable Hardware Acceleration {web link}

Thank You!!! This was driving me nuts. Allowing websites to choose own fixed it.

Roger

Glad to help. Safe Surfing.