You should probably be loading the Roboto font via Google Fonts or similar, because my system does not have Roboto installed by default, so it is defaulting to serif in your comparison.
Roboto is already being loaded from google fonts (https://github.com/rsms/interface/blob/b91dd3af/docs/lab/ind...) However, I think Chrome might do something weird where it fails to actually load the font files when later the font family "Roboto" is requested (https://github.com/rsms/interface/blob/b91dd3af/docs/lab/ind...) — a common hack for this issue is to have an invisible element in the document that explicitly uses the font and forces the browser to load it at document-load time. Could try that hack here.
Anyhow, the version of Roboto served from google fonts is an older version and a subset of the "real" roboto, as can be fetched from roboto's source code repository. If you have Roboto installed locally, you probably have the more recent and more complete version installed and will likely want to compare with that (rather than what's on google fonts.)
Anyhow, the version of Roboto served from google fonts is an older version and a subset of the "real" roboto, as can be fetched from roboto's source code repository. If you have Roboto installed locally, you probably have the more recent and more complete version installed and will likely want to compare with that (rather than what's on google fonts.)
Edit: https://twitter.com/stuartpb/status/900484392472109056 points out that @import must be at the beginning of a style declaration. Website has been updated.