Change Page Button Colors?

Could you link to a webpage with the button in question?

If it is just the color of the writing on the button you want to change to red then the quick way is to just edit the stylesheet “style.css” file.
Find the .top-nav a{} selector in the Navigation section and add a color:red; statement between the brackets.
If you want to make sure this doesn’t get reset if you download an update to the theme you should create a “Child Theme” and do the changes to that rather than directly on the parent theme.

Thank you.