@charset

[cistov]

@charset rule currently ends up being part of a selector:
@charset "UTF-8"; html,section { margin:0; padding:0; border:0 }

E.g. one of the GitHub CSS files:
https://a248.e.akamai.net/assets.github.com/assets/github-0c9d87dff5611078dcc29621367346a73a74b001.css