Looks that there is a problem with the font that Firefox tries to use and Firefox uses a different font instead. The Font inspector should show what font is used as a replacement for the corrupted font. You can right-click and select "Inspect Element" to open the builtin Inspector with this element selected. You can check the font used for selected text in the <u>Font tab in the right panel</u> of the Inspector. Note that this is not about the font-family CSS rule, but about the font that Firefox actually uses as shown in the <b>Font</b> tab. *https://developer.mozilla.org/en-US/Tools/Page_Inspector *https://developer.mozilla.org/en/Tools/Page_Inspector/How_to/View_fonts