JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/vue/dist/vue.js"></script>
<script src="https://unpkg.com/@linusborg/vue-simple-portal"></script>


<div id="portalTarget"></div>

<div id="app">
  <div>
		<portal selector="#portalTarget">
			<p>{{ message }}</p>
		</portal>
    <button @click="updateContent">Update Content</button>
	</div>
</div>

CSS

#portalTarget {
  border: 1px solid #f00;
  border-radius: 5px;
  padding: 8px;
  background: lightyellow;
}

#app {
  margin-top: 5px;
  border: 1px solid #00f;
  border-radius: 5px;
  padding: 8px;
}

JavaScript

new Vue({
  el: '#app',
  
  data: () => ({
    message: 'This content is served from within the app.'
  }),
  
  methods: {
    updateContent () {
      this.message = 'And it is fully reactive!'
    }
  }
})