It’s OK for your headings to be a different color than your regular content text. If anything, I’d suggest it, since color will help give a little emphasis to the headings and make it easier for viewers to scan the page. I would keep colors consistent across your site though — if you change the colors/font sizes/etc per page it may introduce small amounts of confusion for the viewer. You want to keep everything consistent so the user gets a feel like everything belongs together (which will make the site feel more professional).
I’d say this is personal opinion though — whether your headings and content text are different colors just depends on the design of your site.
