lwc:dom="manual" is simply a no-op when using native shadow, but lwc:dom="synthetic-portal" does not work when using native shadow, that difference could be misleading. Create a JavaScript file that looks like this: class MyLightningWebComponent extends LightningElement { }. Web components use browser’s native API support to render UI which reduces the overheads of using other JS libraries and CSS. Shadow Dom have their own little kingdom and cannot be styled from outside, except if they would provide … src: url(https://fonts.gstatic.com/s/opensans/v18/mem6YaGs126MiZpBA-UFUK0Zdcg.ttf) format('truetype'); @font-face { I've been able to check that the CSS classes within those nodes do not appear when inspecting the (Shadow) DOM with Chrome DevTools. @font-face { font-style: normal; lwc:dom="manual" is simply a no-op when using native shadow, but lwc:dom="synthetic-portal" does not work when using native shadow, that difference could be misleading. Shadow DOM is one of the key browser features that make up web components. Packages 0. For example, we might want our to look like this: . Native Shadow DOM: Native Shadow DOM is by default enabled in LWC Open Source. We don’t need a thick framework layer in-between, which could harm our component performance. font-display: swap; If you'd like to know more, they've got a video on the shadow DOM, as well as custom elements and HTML templates. I believe in LWC the shadow DOM will make the CSS inaccessible to child components. Shadow DOM is a web standard that encapsulates the elements of a component to keep styling and behavior consistent in any context. src: url(https://fonts.gstatic.com/s/catamaran/v7/o-0bIpQoyXQa2RxT7-5B6Ryxs2E_6n1iPKba5a7dvg.ttf) format('truetype'); Shadow DOM is a web standard that encapsulates the elements of a component to keep styling and behavior consistent in any context. Elements are the basic foundation of every HTML page. For example, a div tag holds multiple items, a span can wrap phrases, and lis can compose ordered (ol) or unordered (ul) lists. De récents ajouts aux normes Web ont introduit le concept d'un shadow DOM. Shadow DOM is a web standard. Chaque composant Web devrait suivre le même modèle: créer un constructeur et utiliser attachShadow pour ajouter l'élément au shadow DOM. In one sense, these frameworks worked well. Vous créez un fichier JavaScript séparé et y configurez votre élément: class MyWebComponent extends HTMLElement { constructor() {   super();   this.attachShadow({mode: "open"}); } connectedCallback() {   console.log(this.shadowRoot.querySelector("h1")); } }. This document shows how to use the simpler CSS/xPaths that calls through document.querySelector to locate elements within #shadow-root of your Web Components or Salesforce LWC Applications. In a grid layout I have a particular content element (region of the display) that will display different web components or cloned light DOM fragments imported from files. Copy all that same