title: How to use twitter bootstrap-sass mixins
body: <p>Using Rails 3.</p>
  
  <p>Right now in each new <code>.css.scss</code> file that I am creating, I want to be able to use the <code>mixins</code>, but I just couldn't seem to use it.</p>
  
  <p>Here is my <code>bootstrap_import.css.scss</code>:</p>
  
  <pre><code>// Import bootstrap
  // --------------------------------------------------
  @import "bootstrap";
  @import "bootstrap-responsive";
  @media (min-width: 1200px) {
    .span12, .container {
      width: 1170px;
    }
  }
  @import "base";
  </code></pre>
  
  <p>When I have another file called <code>a.css.scss</code> and I try to <code>@include border-radius(12px);</code>, but it just gives this error:</p>
  
  <pre><code>Undefined mixin 'border-radius'.
  </code></pre>
  
  <p><strong>Same goes to <code>variables</code>, I would like to change some colors on some variables so that I can use it on any file without needing to include in each CSS file.</strong></p>
  
  <p>Thank you.</p>