Open UI| open-ui.org
5.4. The ‘symbol’ element| svgwg.org
1. Default Styles for Custom Elements| drafts.csswg.org
The :where() CSS pseudo-class function takes a selector list as its argument, and selects any element that can be selected by one of the selectors in that list.| MDN Web Docs
The :is() CSS pseudo-class function takes a selector list as its argument, and selects any element that can be selected by one of the selectors in that list. This is useful for writing large selectors in a more compact form.| MDN Web Docs
The :focus-visible pseudo-class applies while an element matches the :focus pseudo-class and the UA (User Agent) determines via heuristics that the focus should be made evident on the element. (Many browsers show a "focus ring" by default in this case.)| MDN Web Docs
InfraUnicode and Encoding| html.spec.whatwg.org
The :not() CSS pseudo-class represents elements that do not match a list of selectors. Since it prevents specific items from being selected, it is known as the negation pseudo-class.| MDN Web Docs
The functional :has() CSS pseudo-class represents an element if any of the relative selectors that are passed as an argument match at least one element when anchored against this element. This pseudo-class presents a way of selecting a parent element or a previous sibling element with respect to a reference element by taking a relative selector list as an argument.| MDN Web Docs
1. Default Styles for Custom Elements| drafts.csswg.org
HTML| html.spec.whatwg.org
A deep-dive into the CSS :has parent selector with some use-cases and examples.| ishadeed.com
HTML| html.spec.whatwg.org
HTML| html.spec.whatwg.org
:defined:defined| html.spec.whatwg.org
HTML| html.spec.whatwg.org
jQuery: The Write Less, Do More, JavaScript Library| Official jQuery Blog