I'd like to style web notifications with CSS. In the very least to be able to use background, border and color properties.
Note that I'm talking about actual native web notifications, not alternatives.
For those unaware of what web notifications are you can view the specification here...
Notifications cannot be styled, period. They're explicitly meant to be presentation independent. They could be displayed in a thousand different ways; as desktop popup, as in-browser popup, as SMS notification, as line in a log file... you get the idea. You can provide the content of the notification, the presentation is entirely up to the presenting system.