Best Answer James B† , 23 May 2013 - 10:59 PM
You're code is correct, I've just pasted it into my site and I get the blue/black gradient.
Try pasting it into the custom code box in Pagelines>site options>custom code to see if it works there like mine did. If it does then it might be some of the code above in your style.css of the customise plugin, if there's any errors in the code it will stop any of the css below from being read properly. So check for closing brackets at the end of each section etc.Go to the full post