I´m still testing the Omega theme, and trying to get its templates and css files to work out for me. I´ve already read at the documentation and issues´ replies at Drupal forums.
Think of global as the 'mobile first' template and this this is where most of your css will go.
Ok, so for mobile I use only global.css and for other resolutions I use all the other templates.
The default template is for desktop resolutions where the css is different for that of mobile. The remaining templates are really just for exceptions and other values to address scaling up to wider resolutions.
This is what confuses me, because the other css files are narrow, normal and wide. So I think narrow should be for 7" screens, normal for 10" screens and wide for all the other, bigger screens (usually the desktop). So where fits default template?
Try resizing your browser window to see the changes between layouts.
I´ve tried that, setting just a line of code in every css file, determinig different body background colors for each case. global.css showed on the mobile screen. global.css showed on the 7" tablet on portrait mode. narrow.css showed on the 7" tablet in landscape mode. normal.css showed on the 10" netbook. wide.css showed on the 19" desktop screen.
The color that I´ve set at the default.css file didn´t showed. I´ve took mozilla firefox and resized the browser manually, and all the other templates showed just fine, but default settings never appeared.
I´ve asked this at Drupal community forums, but I would like to know what you think about this. Thanks!