title: How to support the "increase contrast" option under the Accessibility > Display
body: <ul>
  <li>Xcode 9.2</li>
  <li>macOS High Sierra (10.13.3)</li>
  </ul>
  
  <p>macOS gives users a choice to "increase contrast".</p>
  
  <p><img src="https://i.stack.imgur.com/S8F9E.png" alt="increase contrast under accessibility display settings"></p>
  
  <p>I am trying to support this within a macOS app.
  Specifically, I want to adjust the <a href="https://developer.apple.com/documentation/appkit/nsbox/1429797-fillcolor" rel="nofollow noreferrer">fill of NSBox</a></p>
  
  <p>What's the way to do it?</p>
  
  <p><strong>Update</strong></p>
  
  <p>There is a <code>NSWorkspace.accessibilityDisplayOptionsDidChangeNotification</code> notification however, it doesn't appear to fire.</p>
  
  <p><a href="https://github.com/qnoid/AccessibilityDisplayOptions" rel="nofollow noreferrer">Sample Project</a></p>