title: react font-awesome icon is not showing in css content
body: <p>I'm trying to use fontawesome in React in css content and getting blank square instead of the icon. When using normally with html tag, it's working properly.</p>
  
  <p>I installed the npm react-fontawesome and also pasted the cdn in my public index.html. I do prefer to use it in the old way (such as with pure js) and the normal html tags are working.</p>
  
  <pre><code>&lt;link rel="stylesheet" href="https://use.fontawesome.com/releases/v5.6.3/css/all.css" integrity="sha384-UHRtZLI+pbxtHCWp1t77Bi1L4ZtiqrqD80Kn4Z8NTSRyMA2Fd33n5dQ8lWUE00s/" crossorigin="anonymous"&gt;
  </code></pre>
  
  <p>css:</p>
  
  <pre><code>  .answer-selected::before {
        font-family: FontAwesome;
        content: '\f00c'
    }
  </code></pre>
  
  <p>Same icon is working as a html tag:</p>
  
  <pre><code>&lt;i class="fas fa-check"&gt;&lt;/i&gt;
  </code></pre>
  
  <p>Any ideas?
  Thanks in advance</p>