How do I change default font all over the theme?

I am a user of the Helena Pro theme. I customized the font to 'Lucida Sans Unicode, Lucida Grande, sans-serif' within 'Font Family Options' But headlines of Portfolio, Hero Content, Header Highlight content, Promotion Headline are still in the 'Playfair Display'. Also the 'author name' stays in the 'Playfair Display' font. How can I change those fonts into the ones I prefer?