Where should i create a folder to house my CSS files within my rails app directory??
For Rails 3.1+ apps, you should use the asset pipeline. Place stylesheets in app/assets/stylesheets/
if they are specific to your application. You can also put them at vendor/assets/stylesheets/
if they are external (say if they are stylesheets for a javascript plugin.)
After that, you will include stylesheets using the app/assets/stylesheets/application.css
if it is included in your layout file (see other answers for how to do this.)