Issues with H3 Styling: Color and Font Discrepancies

Hmmm... could I get some guidance, please? My H3s are styled to appear purple, in Oswald, and they preview as expected – but: 1) in the published web view, they're all showing in the correct font, but black instead of purple. 2) In the email view, they're showing in the correct colour, but as Montserrat instead of Oswald.