Darkmode¤
Pages are rendered based on your browser's preference, regarding dark mode:

How¤
Through a media query we adapt the colorscheme to the preferred one of the browser:
 
    <body dir="ltr" data-md-color-scheme="preference" data-md-color-primary="yellow" data-md-color-accent="deep-purple">
      
        <script>matchMedia("(prefers-color-scheme: dark)").matches&&document.body.setAttribute("data-md-color-scheme","slate")</script>
      
Linux/Chromium
On Linux do this for chromium, should it not respect your system prefs:
~/.config ❯ cat chromium-flags.conf
--force-dark-mode
--enable-features=WebUIDarkMode