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

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

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

Method: Applies `$this->matchingUninlinableCssRules` to `$this->domDocument` by placing them as CSS in a `