Obsolete detail.editor.css

Thanks for this plugin, this is definitely superior to the CKEditor Accordion!

Pondering while overriding the editor CSS provided by the module: should CSS be delivered at all? Removing it would not harm the functionality.

Native browser support given, the element is distinguishable enough and CKEditor can inherit from custom themes. I guess I'm not the only one preferring to not reset background color, rounded corners etc. before the theme's generic styles looks like intended ;-)