app/assets/stylesheets/rails_admin/custom/variables.scss
/*
Customize Sass variables from Twitter-Bootstrap/RailsAdmin theme or add new ones for your own use.
Copy this file to your app/assets/rails_admin/custom/variables.scss, leave this one untouched
Don't require it in your application.rb
Available variables to use/override:
https://github.com/twbs/bootstrap-sass/blob/master/assets/stylesheets/bootstrap/_variables.scss
https://github.com/railsadminteam/rails_admin/blob/master/src/rails_admin/styles/base/variables.scss
Plus the ones from your themes.
Test me: pink links
$link-color: #F0F;
*/