Rody Davis (@rodydavis.com)

Using shadow DOM - Web APIs | MDN 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. https://developer.mozilla.org/en-US/docs/Web/API/Web_components/Using_shadow_DOM