title: Change background color of button in Bootstrap 4
body: <p>I want to change the color of a button in Bootstrap 4 Alpha 6.</p>
  
  <p>In my _custom.scss I include:</p>
  
  <pre><code>$brand-primary:             $purple;
  </code></pre>
  
  <p>But to make the button change color from blue to purple I must also include:</p>
  
  <pre><code>$btn-primary-bg:                 $purple;
  </code></pre>
  
  <p>Shouldn't it be enough to include the first line?</p>
  
  <p>This is all I have in my custom file. </p>
  
  <pre><code>$purple: #a02971;
  $brand-primary: $purple;
  $enable-rounded: false;
  </code></pre>
  
  <p>The last line successfully removes the rounded corners of my button, so I know my recompilation of the sass-files are working. But when I look in the generated css, the button background color remains the default blue.</p>