On some web pages the lettering is eerily similar to the ink running. Often one line appears over to of another.
I have attempted changing the font size but I get the same result.
Reset the page zoom on pages that cause problems: View > Zoom > Reset (Ctrl+0 (zero); Cmd+0 on Mac)
If you have increased the minimum font size then try the default setting "none" as a high value can cause issues like you described.