title: Bootstrap breakpoint viewport sizes
body: <p>I'm building a multi-device cropping tool using cropperjs. At the moment I'm guessing viewport sizes at each bootstrap breakpoint, but I'm not sure what the real height is (so I can create a ratio). You can find the grid width breakpoints here: <a href="https://github.com/twbs/bootstrap/blob/v4-dev/scss/_variables.scss" rel="nofollow noreferrer">https://github.com/twbs/bootstrap/blob/v4-dev/scss/_variables.scss</a> (lines 168-174)</p>
  
  <p>To summarise, I'm looking for the viewport sizes at each breakpoint: <code>sm, md, lg, xl</code>. I could research the most common device size (I may still do this), but I'd prefer something that relates to bootstrap's sizing. Thank-you.</p>
  
  <pre><code>sm: {
      width: 576px,
      height: ...
  }
  md: {
      width: 768px,
      height: ...
  }
  lg: {
      width: 992px,
      height: ...
  }
  xl: {
      width: 1200px
      height: ...
  }
  </code></pre>