How to change the font on a SharePoint site

Method 1 

Using IE open the Developer Tool (F12) > Cick  Find, Element by Click > then CSS, then click on the element you want to change the Developer Toolbar will tell you the Div or Tag that is being used to Style the Font your talking about.  Then use Heather Solomons Chart of CSS Elementshttp://www.heathersolomon.com/content/sp07cssreference.htm. Heather lists the Style Sheet being used and the line # of the Tag or Div with an image so you can easily see what you need to modify.


Method 2

you can create a new theme all together and deploy it.

Creating themes is an easy method -

To create a new theme

1. Start Microsoft Word 2010.
2. In the Ribbon, click the Page Layout tab.
3. In the Themes group, display the Colors menu. Choose Create New Theme Colors. Choose the colors you want to use for the new theme. Provide a name, and then click Save.
4. In the Themes group, display the Fonts menu. Choose Create New Theme Fonts. Choose the fonts that you want to use for the new theme. Provide a name, and then click Save.
5. In the Themes group, display the Themes menu. Choose Save Current Theme.
6. In the Save Current Theme dialog box, supply a name for the new theme. Pick a convenient location for the .thmx file, such as the Desktop, and then click Save.

After the .thmx file has been created, you can import it into the SharePoint installation.

To import a theme

1. In Enterprise Portal, browse to the main Enterprise Portal site.
2. In the Site Actions menu, click Site Settings.
3. In the Galleries group, click Themes.
4. In the Ribbon, display the Documents tab.
5. In the New group, click Upload Document.
6. Click Browse. Select the .thmx file that you created, and then click Open.
7. Click OK to upload the new theme.
8. Verify the name for the theme. You can also provide a description of the new theme. Click Save.