If it was written by a human, none of this would be javascript except the next button click handler. I don't know what is going on that it mentions a service wo

If it was written by a human, none of this would be javascript except the next button click handler. I don't know what is going on that it mentions a service worker at the end. That's wild. Anyway the CSS is missing a transition for the width. That's why it's jerky.