Just in case anyone is still forced to use #WhatsApp and wants to install it as a #ChromeWebApp but immediately dies from
`#FFFFFF`: You can force the #titlebar color from #light to #dark.

1. "Uninstall" existing WhatsApp web app
2. Navigate to https://web.whatsapp.com
3. Open Developer Tools (F12 / "Inspect")
4. Find `theme-color` HTML meta tag and change its value to `#111b21`
5. "Install" as web app
5. Relax your eyes 

The biggest thing I've hated on solely relying on websites is the lack of a separate process with its own icon. Stuff just gets lost if you have a ton of browser tabs open.
Enter #ChromeWebApp. You just click once and boom. It's installed, has its own window, icon and notifications with very little disk space usage.

Does Edge, Firefox and other browsers have this? I think it's a game changer!