title: Can I use both px and em in the same style sheet?
body: <p>I wanted to know If I can use both px and em in the same CSS file (for same tags/class). What I mean by this is that, can I have something like this : -</p>
  <pre><code>body{
      font-size: 10px; 
      font-size: 0.625em;
      font-weight: normal;
      font-family: arial;
      margin: 0px auto;
      color: #333333;
      background: #E0E0E0;
  }
  </code></pre>
  <p>My objective is to convert a very big CSS file that supports 'em' so that the user can decide the font size they would like to use. But my problem is the well documented issue with 'em' - the nested tags get affected.</p>
  <p>I sought for help by using 'rem' in certain places instead of 'em'. Though it helped a bit, I lost the entire structure of the webpage.</p>
  <p>I would like to keep the exact same font size in my webpage and still support the user wanting to change font size.</p>
  <p>I am using jQuery to add a class to the body tag that would contain a specified font size and everything else should be scalable.</p>