import { ShadyCSS } from '@webcomponents/shadycss/index.js'; ShadyCSS.styleElement(this.shadowRoot.host); import { ShadyCSS } from '@webcomponents/shadycss/index.js'; ShadyCSS.applyStyle(this, ':hover', 'background-color: red;'); import { ShadyCSS } from '@webcomponents/shadycss/index.js'; ShadyCSS.styleCustomProperties(this, { '--my-custom-color': 'blue', });