Method: Checks whether there is at least one matching element for the CSS selector contained in the `selector` element of the provided CSS rule.

Method: Maps a CSS selector to an XPath query string.

Method: Removes pseudo-elements and dynamic pseudo-classes from a CSS selector, replacing them with “*” if necessary.

Method: Flexibly translates the CSS selector $trimmedLowercaseSelector to an xPath selector.

Method: Helps `removeUnmatchablePseudoComponents()` replace or remove a selector `:not(.

Method: Checks whether there is at least one matching element for $cssSelector.

Method: Returns CSS content.

Method: Adds a style element with $css to $this->domDocument.

Method: Checks that $this->domDocument has a BODY element and adds it if it is missing.

Method: Removes comments from the supplied CSS.