I've checked your site and seems like the module.css is not loaded because you places your module in the tab. I've manually paste the css code from module.css into your template.css and now it is displayed correctly. Please have a look.
I believe when you do upgrade, only the core file is override as such module.css is a core file. But template.css file is not be override if you do update.
Hope this will help and if you have anymore question, please don't hesitate to ask us.
Thanks.