Problem with using @import in themes style.css

There is a problem with TinyMCE itself where the stylesheet that loaded from your theme's CSS will not correctly load @imported CSS files.
For instance, if your style.css looked like:

body {
  background-color: red;
}
@import "font.css"

then the editor (if you've selected 'use theme CSS' in Editor CSS on tinymce settings page) would with a red background, but none of your font attributes would be loaded. This seems to be a known issue on the TinyMCE forums, but I couldn't find a way around it.