Can we do back-end web programming with flutter for web?

I am an android app developer but I am looking to learn full stack web development. Recently, I heard that flutter announced their web platform which allows to make websites. I wanted to ask that can we become a full stack web developer with flutter for web, can we do both front end and back end web programming with flutter for web. I am asking this because I already know how to develop mobile apps using flutter and wondering if I need to learn HTML CSS Javascript mongodb django etc. So should I wait for flutter for web to become stable and then develop websites using flutter, or I should learn those languages(HTML CSS etc) for website development?