If you look at the docs you'll see it's not trying to replace CSS and HTML (thankfully). CSS and HTML are still used. There just appears to be some extra sugar

If you look at the docs you'll see it's not trying to replace CSS and HTML (thankfully). CSS and HTML are still used. There just appears to be some extra sugar around HTML templating (and it checks your HTML at compile-time). The 'one unified language' therefore just refers to using a single language on client and server, and as it happens it's a JavaScript like language, so simply in terms of languages used it's not all that different to using JS on the client and server. The main selling point of this appears to be strong static typing. Edit: Also yes, glad they are rethinking the licensing.