::slotted()

Baseline Widely available

This feature is well established and works across many devices and browser versions. It’s been available across browsers since January 2020.

The ::slotted() CSS pseudo-element represents any element that has been placed into a slot inside an HTML template (see Using templates and slots for more information).

This only works when used inside CSS placed within a shadow DOM. Note that this selector won't select a text node placed into a slot; it only targets actual elements.

Try it

/* This CSS is being applied inside the shadow DOM. */

::slotted(.content) {
  background-color: aqua;
}

h2 ::slotted(span) {
  background: silver;
}




  Error
  Build failed!

customElements.define(
  "my-card",
  class extends HTMLElement {
    constructor() {
      super();

      const template = document.getElementById("card-template");
      const shadow = this.attachShadow({ mode: "open" });
      shadow.appendChild(template.content.cloneNode(true));

      const elementStyle = document.createElement("style");
      elementStyle.textContent = `
        div {
          width: 200px;
          border: 2px dotted red;
          border-radius: 4px;
        }`;
      shadow.appendChild(elementStyle);

      const cssTab = document.querySelector("#css-output");
      const editorStyle = document.createElement("style");
      editorStyle.textContent = cssTab.textContent;
      shadow.appendChild(editorStyle);
      cssTab.addEventListener("change", () => {
        editorStyle.textContent = cssTab.textContent;
      });
    }
  },
);

css

/* Selects any element placed inside a slot */
::slotted(*) {
  font-weight: bold;
}

/* Selects any  placed inside a slot */
::slotted(span) {
  font-weight: bold;
}