Most of the standard Pressero skins utilize Arial as their default font. A few use Tahoma or Times New Roman. These three fonts are used because they are available in every browser.
If you would like your site to use a different font, then you can accomplish that through a custom skin. Please note that you would still be limited to fonts that are available in the Google font library
or to a WOFF
font, so that the text on your site will work in all browsers.