If you create a style.css file for a WordPress theme on a Mac OSX server it will use Mac line breaks (\r) instead of Unix (\n) or Windows (\r\n) ones. get_theme_data() won’t parse the metadata correctly, and it will be look messed up in the admin panel, or break the theme entirely. If your text editor supports converting between the different styles, then that’s all you need to do to fix it.