Deno can import this

index.js

class MyTitle extends HTMLElement {
  connectedCallback() {
    this.innerHTML = `
      <style>
        h1 {
          font-size: 2.5rem;
          color: hotpink;
          font-family: monospace;
          text-align: center;
          text-decoration: pink solid underline;
          text-decoration-skip: ink;
        }
      </style>
      <h1>Hello Alligator!</h1>
    `;
  }
}

customElements.define('my-title', MyTitle);