title: Does BS4 offer a means to size `.input-group` down on various devices
body: <p>I'm looking to size a BS4 input-group down as and when it is loaded on various devices. Kinda like how you can tell a col what it should be displaying on various screens. I.e.</p>
  
  <p><code>&lt;div class="col-12 col-md-6 col-lg-4"&gt;&lt;/div&gt;</code></p>
  
  <blockquote>
    <p>I want to do something similar on mobile devices, I.e. on a desktop
    use <code>.input-group-lg</code> on a mobile use <code>.input-group-sm</code> etc.</p>
    
    <p>Is this something BS4 can do? (I can't see any mention of it in the
    docs?)</p>
  </blockquote>
  
  <p>Here's a <a href="https://jsfiddle.net/Beaniie/tkmujo9q/20/" rel="nofollow noreferrer">jsfiddle</a> with an example, if it helps.</p>