You can try to set the pref gfx.font_rendering.harfbuzz.level from the default 2 to 1 to see if that helps.

To open the about:config page, type about:config in the location (address) bar and press the "Enter" key, just like you type the url of a website to open a website.
If you see a warning then you can confirm that you want to access that page.
You can use the Filter bar at to top of the about:config page to locate a pref more easily.

thanks i did it and did anther think. it is uncheck on allows pages chose their fonts .... in parts of fonts &color they help me