title: Sass::SyntaxError: Undefined mixin 'mixin_name'
body: <p>I'm working on a Rails 4 project where I'm using Sass and Sass's @import to combine multiple css into one. It works fine but not if I use a new partial for mixins (<code>_mixins.css.scss</code>) and @import this in <code>main.css.scss</code> only and use mixins any other file which is added after that <code>_webapp.css.scss</code></p>
  
  <pre><code>    @import "bootstrap/bootstrap";
      @import "responsive/mega_menu";
      @import "responsive/mixins";
      @import "responsive/webapp";
  </code></pre>
  
  <p>Rails Precompilation process is unable to find "<code>responsive/mixins</code>" and gives error in <code>_webapp.css.scss</code></p>
  
  <pre><code>Sass::SyntaxError: Undefined mixin 'mixin_name'.
  </code></pre>
  
  <p>here <code>mixin_name</code> is defined in <code>responsive/mixins</code> </p>