title: Is it possible to set empty string as a class selector in sass?
body: <p>I have a variable which have empty string as default value and it can be changed dynamically based on skin name. So I tried to write my sass selector like this.</p>
  
  <p><strong>default.scss:</strong></p>
  
  <pre><code>$skin: '';
  </code></pre>
  
  <p><strong>green.scss:</strong></p>
  
  <pre><code>$skin: 'green';
  </code></pre>
  
  <p><strong>main.scss:</strong></p>
  
  <pre><code>@import 'default.scss';
  .#{$skin} .header{
      color: black;
  }
  </code></pre>
  
  <p>So I expected the below output from generated CSS.</p>
  
  <pre><code>.header{
    color: black;
  }
  </code></pre>
  
  <p>and </p>
  
  <pre><code>.green .header{
     color: black;
  }
  </code></pre>
  
  <p>But it throws below error while compiling 
  <strong>Invalid CSS after ".": expected class name, was ".header"</strong></p>