Hint markers with flat styling

I :heart: that users have the ability to customize the hint markers in Vimium and I have been using this look which I'm really liking.

![](https://camo.githubusercontent.com/6e164c42becc71f33d22eee30cc972f6c3b95f6e/687474703a2f2f636c2e6c792f696d6167652f3144336732513041313733492f636f6e74656e74/content)

@philc Would you be interested in using something like this as the default style? No worries if not – I can keep rocking my custom version.