Stylesheet is not rendered when access externally

Hi all,
this problem has haunted me for days. I did a bit of googling and found this https://wiki.archlinux.org/index.php/Wordpress#Appearance_is_broken_.28no_styling.29 and https://www.ads-software.com/support/topic/page-displays-fine-locally-but-not-externally-wamp?replies=5 . My problem is exactly the same as described in the latter link post. Both suggest that there should be a problem with my host name but I have no idea how to fix it. I am running Arch Linux on my server. Can someone show me what exactly do I have to do to resolve this issue? Thanks in advance