WordPress Offline ???

Hello,

I’m realize a Info Screen with a Raspberry Pi. But when the Raspi is Offline the Site will show not Correct. No Images, Fonts or anything is right.

When i’m online everything is ok… WHY ???

My System:

Raspberry Pi Model B with Debian (newest version)
Wordpress 3.9.1
Theme: http://pixelydo.com/work/wordpress-digital-signage/

I Hope you can help mee