Can you provide sites and steps to replicate the issue?

[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".

"Allow Web Sites To Choose Their Own" was checked. I don't have uBlock Origin that I know of.

The screenshot is from https://app.elisiapp.com/#/ And I'm using Windows 10

Okay, unchecking "Allow Web Sites To Choose Their Own" fixed the site I screenshot, but now gmail looks weird.

Did you check out everything in my post? https://support.mozilla.org/en-US/questions/1359622#answer-1463216

I don't really know how to address " 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. "

I don't think I downloaded new versions of them, or blocked anything. I've downloaded fonts from Adobe, and one called "Ride" but I didn't... I don't know, do anything weird with them.

This website specifies various Helvetica variants if I check this in the Inspector, so this could an issue with Helvetica fonts.

.jSHaPE {
	font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
	color: inherit;
	cursor: pointer;
}

.fNIskD {
	font-family: "HelveticaNeue-Light", "Helvetica Neue Light", "Helvetica Neue", Helvetica, Arial, "Lucida Grande", sans-serif;
	color: rgb(56, 56, 56);
}

You can right-click and select "Inspect Element" to open the built-in Inspector with this element selected.

• https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Examine_and_edit_HTML

You can check in the Rules tab in the right panel in the Inspector what font-family is used for selected text. You can check in the Font tab in the right panel in the Inspector what font is actually used because Firefox might be using a different font than specified by the website.

• https://developer.mozilla.org/en-US/docs/Tools/Page_Inspector/How_to/Edit_fonts

Cor-el,

I don't see "Rules" on my inspector, but I could change the size of some words, and they still have pieces missing. (Attached)

Can I tell firefox to use a different font for this site? Or like, how do I even fix Helvetica if that's the problem somehow?

Oh, I did install Helvetica Neue to make a facebook mock-up. So... how can I uninstall a font in Windows? Without breaking something else?