Function new_from_str 

pub fn new_from_str<'a>(css_string: &'a str) -> (Css, Vec<CssParseWarnMsg<'a>>)

Parses a CSS string into a Css value and a list of recoverable warnings.

Never panics. Syntax errors and unsupported properties are collected as CssParseWarnMsg items rather than causing a hard failure, so the caller always receives a (possibly empty) stylesheet.