The client's selected font displays fine on Chrome, Opera and Safari. But in Firefox and IE the font reverts to what appears to be a sans-serif. In Firefox the Web Console shows the following
[18:20:19.616] downloadable font: no supported format found (font-family: "Calibri-Bold" style:normal weight:normal stretch:normal src index:4)
source: (end of source list) @ http://www.amarilloopera.org/wp-content/themes/opera_site/style.css
Obviously the font does exist since it works in other browsers.
I have found several possible solutions that all involve modifying the Apache configuration file, but the site is hosted and we do not have access to the .conf file.