This was a great little patch that made it very clear and consistent how to add CSS files in Drupal. In 4.7, adding CSS files was a bit of a mystery, as I outlined in a previous Lullabot article. Now, starting with 5.0, it’s very easy: drupal_add_css($cssFile, $type = 'module'). That’s it. Just specify the type of CSS file, core, module, or theme, and this function will handle the rest, loading them in a correct and consistent cascading order."
Bryan Ruby is the owner and editor for CMS Report. He founded CMSReport.com in 2006 on the belief that information technologists, website owners, and web developers desired visiting sites where they could learn about content management systems without the sales pitch. Besides this site, you can follow Bryan at Google+ and Twitter.