I am currently inside a Developer Sandbox within Salesforce. Inside the developer console I am able to create static resources of the MIME type text/CSS. I know this because they show up when I display static resources:
Normally, it appears for non-developer orgs, but I also get this following error window as well:
Which leads me to believe something more subtle is going on.
Regardless, how do I properly load a CSS static resource in a developer org?