There is an easier way by specifying a theme:
$mdToast.simple().content("some test").theme("success-toast")
And in your CSS:
md-toast.md-success-toast-theme {
background-color: green;
...
}
You could incorporate your message type to dynamically select a theme.
Update:
As Charlie Ng pointed out, to avoid warnings regarding use of an unregistered custom theme register it in your module using the theme provider: $mdThemingProvider.theme("success-toast")
Another update:
There was a breaking change created on 2 Dec 2015 (v1.0.0+). You now need to specify:
md-toast.md-success-toast-theme {
.md-toast-content {
background-color: green;
...
}
}