title: R - different font sizes when using atop
body: <p>Creating a plot where the y-axis has two lines. I'm using the atop function as follows:</p>
  
  <pre><code>plot + ylab(expressions(atop("Line 1","Line 2")))
  </code></pre>
  
  <p>Wondering whether it would be possible to change line 1's font size i.e., make it larger than line 2?</p>
  
  <p>Thanks!</p>