title: Navigation Mobile dropdown, make size of screen
body: <p>I have a dropdown menu on my WordPress website, which displays all of the pages listed.</p>
  
  <p>But I want to make this dropdown navigation fill the height of the screen.</p>
  
  <p>So far, I am targeting <code>#main-nav-ul</code>
  If I set a height on this, it affects the height of the dropdown.</p>
  
  <p>I understand I need to be able to detect the screen size, using JavaScript, then pass this to the height?</p>