How to include CSS for a custom admin theme? I want to include my custom style.css in admin pages in Custom Admin theme I have been create.
I am including CSS in .info file as follows

name = Example Module
description = Custom Example Module
core = 7.x
configure = admin/config/example-module/settings
permissions = admin/people/permissions#module-example-module
stylesheets[all][] = css/style.css


and I used mymodule_preprocess_page(&amp;vars) , but I didn't see any result.
You can add yourstyl.css in admin theme's .info file.
Just goto your active admin theme, find and open its .info file and place a simple line here; stylesheets[ ] = css/yourstyle.css . It works like a charm.