Loading Google font in HTTPS, content being blocked

Use protocol relative URIs

Just use a // prefix. (instead of http[s]://)

• On an https page, the secure version wil be loaded.
• On on a plain http page, the plain http version will be loaded.

Edit your theme replacing every occurence of http://fonts.googleapis.com/... with //fonts.googleapis.com/...

Edit your theme replacing every occurence of http://fonts.googleapis.com/... with https://fonts.googleapis.com/... (mind the s).

Resources that might pose a security risk (such as scripts and fonts) must be loaded through a secure connection when requested in the context of a secured page for an obvious reason: they could have been manipulated along the way.