title: Detect if the browser is using dark mode and use a different favicon
body: <p>Google Chrome 73 has been released, and it adds "dark mode" support to the browser. I notice that a lot of favicons look bad now.</p>
  
  <p><a href="https://i.stack.imgur.com/po2wG.png" rel="noreferrer"><img src="https://i.stack.imgur.com/po2wG.png" alt="Dark mode Wikimedia Foundation tab screenshot"></a></p>
  
  <p><a href="https://i.stack.imgur.com/FjZAu.png" rel="noreferrer"><img src="https://i.stack.imgur.com/FjZAu.png" alt="Dark mode Codecademy tab screenshot"></a></p>
  
  <p>Is there a way to detect if the user is using dark mode and change the favicon?</p>