Font size and color on some parts of my site spontaneously changed

Recently on all of my pages some of my text changed from black to orange and also changed the font size. I did not do this. I have tried to correct this but have not had any luck. I contacted the theme’s developer but he says that it isn’t on his end.

I have another website which uses the same template that does not have this problem. At the theme developer’s suggestion I deactivated the plug-ins that weren’t common between the two, assuming that the ones that were used on both weren’t a problem as the other website doesn’t have the issue.

I would very much appreciate suggestions.

The page I need help with: [log in to see the link]