title: How to change the background colour's opacity in CSS
body: <p>I have a PNG file which I give a background colour to its transparent areas, but I would like to make the background colour a bit transparent, like opacity. Here is my code so far:</p>
  
  <pre><code>social img{
      opacity:0.5;
  }
  .social img:hover {
      opacity:1;
      background-color:black;
  }
  </code></pre>