title: @apply from Gridsome's Tailwind plugin does not work
body: <p>I want to use Tailwinds apply feature in my Gridsome project. But error gets thrown that css classes from tailwind cannot be found.</p>
  
  <p>Steps to reproduce:</p>
  
  <p>1) Create new Gridsome project</p>
  
  <p>2) Install tailwind plugin
  <a href="https://github.com/brandonpittman/gridsome-plugin-tailwindcss" rel="nofollow noreferrer">Github page</a>
  <a href="https://www.npmjs.com/package/gridsome-plugin-tailwindcss" rel="nofollow noreferrer">Npm page</a></p>
  
  <p>3) Create css file in assets folder and import in main.js</p>
  
  <pre><code>import "~/assets/style.css"
  </code></pre>
  
  <p>4) Create css class in css file</p>
  
  <p>5) Use @apply in css with tailwind component</p>
  
  <p>Nothing happens... css file is properly imported bacause normal css gets applied
  Some elements like rounded seem too work but others like bg-blue-500 dont. </p>