hello-world.html

<link rel="import" href="template-component.html">
<script>
  class HelloWorld extends TemplateComponent {
    constructor() {
      super(HelloWorld.is);
    }

    static get is() {
      return 'hello-world';
    }

    getState() {
      return {
        hello: "world"
      };
    }
  }

  window.customElements.define(HelloWorld.is, HelloWorld);
</script>
<template>
  <style>
    /* This is scoped!  */
    
    p {
      color: blue;
      font-weight: bold;
    }
  </style>
  <h1>Welcome!</h1>
  <p>Awesome song is ${this.world}</p>
</template>