The Element.attachShadow() method attaches a shadow DOM tree to the specified element and returns a reference to its ShadowRoot.| MDN Web Docs
Chris Haynes - web developer consultant| lamplightdev.com
1. Introduction| drafts.csswg.org
Shadow DOM promises to allow developers to create more maintainable, cross-framework components, but there is an as-yet unsolved conundrum for accessibility.| alice.pages.igalia.com
An important aspect of custom elements is encapsulation, because a custom element, by definition, is a piece of reusable functionality: it might be dropped into any web page and be expected to work. So it's important that code running in the page should not be able to accidentally break a custom element by modifying its internal implementation. Shadow DOM enables you to attach a DOM tree to an element, and have the internals of this tree hidden from JavaScript and CSS running in the page.| MDN Web Docs
You've probably used visually-hidden content before. But how does the CSS actually work, and why do we use those particular properties?| TPGi