WTF?! The bar word above should be rendered in red, but it's not! That sucks. It's because ANSI codes are linear, not hierarchical (as with XML/HTML). A special kind of magic is needed to make this ...
CSS Validator built on CSSTree. Technically, the package utilizes the capabilities of CSSTree to match CSS syntaxes to various parts of your code and generates a list of errors, if any.