Failed to execute 'attachShadow' on 'Element'

This library seems really useful but I'm having some issues getting it running.

I'm getting the following error while trying to run the basic editor:

Uncaught DOMException: Failed to execute 'attachShadow' on 'Element': This element does not support attachShadow
    at minimalEditor (https://icrann.irish/float/prism-code-editor/setups/index.js:22:38)
    at basicEditor (https://icrann.irish/float/prism-code-editor/setups/index.js:39:18)
    at https://icrann.irish/float/index.js:5:16

My code is below:

<!DOCTYPE html>
<html lang="en">
    <head>
        <meta charset="UTF-8">
        <meta name="viewport" content="width=device-width, initial-scale=1.0">
        <title>Float</title>

        <script type="module" src="index.js"></script>
    </head>
    <body>

        <textarea id="editor"></textarea>

    </body>
</html>

import { minimalEditor, basicEditor, fullEditor, readonlyEditor } from "./prism-code-editor/setups/index.js"
// Importing Prism grammars
import "./prism-code-editor/prism/languages/markup"

const editor = basicEditor(
  "#editor",
  {
    language: "html",
    theme: "github-dark",
  },
  () => console.log("ready"),
)

Thanks for any help.

FIameCaster / prism-code-editor

Failed to execute 'attachShadow' on 'Element' #17