title: CSS in React. Can't darken background-image
body: <p>I have the problem with my background-image on my website (React.js).
  I want to darken the background-image and this darkening does not work.
  I tried <a href="https://stackoverflow.com/questions/26621513/darken-css-background-image">Darken CSS background image?</a> and this doesn't work.
  I am testing in the newest version of Google Chrome browser.
  Here is my code:</p>
  <pre><code>* {
      margin: 0;
      padding: 0;
  }
  
  body{
      background: url(&quot;images/background.jpg&quot;);
  }
  
  header{
      position: absolute;
      width: 100%;
      height: 5vh;
  }
  
  ul{
      position: absolute;
      display: inline-block;
      left: 10vw;
      top: 2vh;
      list-style-type: none;
  }
  
  .link{
      text-decoration: none;
      color: white;
  }
  </code></pre>