title: Sass Syntax Error: wrong number of arguments (1 for 3) for `rgb'
body: <p>I use Ruby On Rails 5 and gem sass-rails 5.0</p>
  <p>For some reason I get an error message:</p>
  <blockquote>
  <p>wrong number of arguments (1 for 3) for `rgb'</p>
  </blockquote>
  <p>in line number 2 of file app/assets/stylesheets/main.css.scss</p>
  <pre><code>$main-color-raw: rgb(0,80,170);
  $main-color: rgb($main-color-raw);
  $main-color-bright: rgba($main-color-raw, 0.5);
  </code></pre>
  <p>I tried with a hex color value instead of rgb():</p>
  <pre><code>$main-color-raw: #0050aa;
  </code></pre>
  <p>But get the same error message.</p>
  <p>It looks like the sass-variable $main-color-raw is not evaluated correctly and maybe is the rails-sass gem configuration wrong.</p>
  <p>So I added in my config/application.rb</p>
  <pre><code>config.sass.preferred_syntax = :scss
  config.sass.line_comments = false
  config.sass.cache = false
  </code></pre>
  <p>from the rails-sass github documentation page.</p>
  <p>But still the same error.</p>
  <p>How can I resolve it?</p>