Summary:

A customer may have a requirement to change the default font for the email editor (FCKeditor). By default, the email editor will default to Times New Roman.

Workaround:

This can be modified for each user theme. The default font for the text editor is set in \CRM\WWWRoot\Themes\FCKeditor\theme name\css\fck_editorarea.css

body, td
{
 font-family: Times New Roman;
 font-size: 16px;
}

Sans-serif fonts are recommended for on-screen use. The following font settings will provide good ClearType support on clients where this is supported, as well as failover for other systems:

font-family: Calibri, Verdana, Arial, Helvetica, sans-serif;