How to configure Rails Assets pipeline to use Formtastic's css

app/assets/stylesheets/application.css

*= require formtastic

I get this error:

rake assets:precompile 
/Users/Nerian/.rvm/rubies/ruby-1.9.3-rc1/bin/ruby /Users/Nerian/.rvm/gems/ruby-1.9.3-rc1@davinci/bin/rake assets:precompile:all RAILS_ENV=production RAILS_GROUPS=assets
rake aborted!
Invalid CSS after "*": expected "{", was "= require formt..."
  (in /Users/Nerian/Projects/davinci/app/assets/stylesheets/application.css)

Tasks: TOP => assets:precompile:primary
(See full trace by running task with --trace)
rake aborted!
Command failed with status (1): [/Users/Nerian/.rvm/rubies/ruby-1.9.3-rc1/b...]

So the rake task doesn't work, but strangely when I run the app in development the assets are compiled since I can see the formtastic css being applied.

What am I doing wrong?

Edit:

/*
 * This is a manifest file that'll automatically include all the stylesheets available in this directory
 * and any sub-directories. You're free to add application-wide styles to this file and they'll appear at
 * the top of the compiled file, but it's generally better to create a new file per style scope.
 *= require_self
 *= require_tr开发者_运维百科ee . 
 *= require formtastic
 *= require my_formtastic_changes
*/

---

Is that line inside a comment group? It should be:

/*
*= require formtastic
*/

I don't think development mode compiles the files, but rather serves them separately, so that may explain why there's no error at that time...

---

Just want to add to the answer in case anyone else has the same problem.

I had this: wrong

/*= require reset
 *= require main
 */

But I needed to change the first line: right

/*
 *= require reset
 *= require main
 */