You can change the font on any part of your site. To change a font just go to the Fonts section of the SNO Design Options page under the Appearance tab in the WordPress dashboard. Choose the font you want from the dropdown menu and click Save All Settings. To see your font in action click the Save All Settings button and go back to your site. Otherwise you can do a Google search for the font name to see what it looks like.
Adding New Fonts
SNO uses Google fonts. Non-Google Fonts are not allowed. To add any font from the Google database of fonts to your site, simply go to the Fonts section of the SNO Design Options page under the Appearance tab in the WordPress dashboard and click the Search for Fonts link. After you have decided on a font, add the name of the font you want added in the box below the link (be sure the name, case, and spacing of the font name are exact). Click Save All Settings and the font you added will now appear at the bottom of all of the font drop down menus. Follow the instructions above to change the various elements of your site to this font.
Font Weights Defined
Font-weight defines the thinness or thickness of a font. The ranges are 100 to 900. Normal font is 400. 700 is bold. So 900 would be an "extra bold" and a 100 would be an "extra light". Some font types have fewer weight options than others, so be sure you only choose a weight that is available in that font type's library. You can see which weights each font allows in the Google Font library here.