My css file is overridden due to activeadmin

What worked for me (Rails 5) was adding the following line on my app/assets/stylesheets/application.css after the *= require_self line:

*= stub "active_admin"

Based on seanlinsley comment on selected answer and nathan's answer too, it seems to me that the 'cleanest' way is indeed to move active_admin.css.scss from app/assets/stylesheets/ to vendor/assets/stylesheets/.

No need to any other (configuration) modification: 'main' app has it's styles back to normal and AA display is normal too.

(I didn't want to manually include each of my ressources instead of require_tree ... !)

This is the way AA is getting into: AA (still) opened issue on the matter.

For active_admin to play nice don't include it in the application.css, i.e.: remove the

require_tree .

and require each file separately inside app/assets/stylesheets but don't put active_admin.css

and on config/production.rb put this

config.assets.precompile += ['active_admin.css']