I'm not sure the issue is related to the CSS files. I think maybe HS does not play exactly nice with Joomla! 3.3.3. The rest of the cart is not displaying correctly either. All the HS files on the Test site are identical to the HS files on the Live site.
This is what I did to make/build the Test site. (The Live site was built before the Test site.)
1. Used Akeeba Backup to make a complete backup of the Live site, which is running HS 2.3.2 on Joomla! 2.5.14.
2. Restored the site using Akeeba Kickstart to the Test site, therefore, HS 2.3.2 is now running on Joomla! 3.3.3.
All HS 2.3.2 files on the Joomla! 3.3.3 Test site are are identical to the HS 2.3.2 that is running on Joomla! 2.5.14.
Does this help any?