"Browser not Supported" with the latest Chromium version.

And then an insulting "Try a modern, up to date browser".

You should not discriminate by user agent. Do feature detection instead:

https://duckduckgo.com/?q=user+agent+vs+feature+detection&t=...

I find this sample much more informative than the entire 'How it works' section. You tool is pretty much self explanatory, so skip the text and modals and just show what it is about directly when you enter the site