Mail inline imported stylesheets

[nandi95]

Turns out that mail with a stylesheet (that will be inlined) cannot import other stylesheets...
It just spits me back the following which matches what I have in my default.css

@import "../styles/base.css";
@import "../styles/buttons.css";

in the Markdown render
Is there a way to overcome that currently?
Is it possible to add this feature to the framework so it resolves the imports?