Nested Headings

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle'
});

styles.app.css

body {
  margin: 12px 16px;
  font-family: 'Helvetica Neue', Helvetica, Arial, sans-serif;
  font-size: 12pt;
}

section {
  padding: 1rem;
	border: solid 1px #ccc;
}

h1 {
  color: red;
	font-size: 2.25rem;
}

h2,
h1 ~ section h1 {
  color: orange;
	font-size: 2rem;
}

h3,
h1 ~ section h1 ~ section h1,
h1 ~ section h2,
h2 ~ section h1 {
  color: gold;
	font-size: 1.75rem;
}

h4,
h1 ~ section h1 ~ section h1 ~ section h1,
h1 ~ section h1 ~ section h2,
h1 ~ section h2 ~ section h1,
h1 ~ section h3,
h2 ~ section h1 ~ section h1,
h2 ~ section h2,
h3 ~ section h1,
h4 ~ section h3 {
  color: green;
  font-size: 1.5rem;
}

h5,
h1 ~ section h1 ~ section h1 ~ section h1 ~ section h1,
h1 ~ section h1 ~ section h1 ~ section h2,
h1 ~ section h1 ~ section h2 ~ section h1,
h1 ~ section h1 ~ section h3,
h1 ~ section h2 ~ section h1 ~ section h1,
h1 ~ section h2 ~ section h2,
h1 ~ section h3 ~ section h1,
h1 ~ section h4,
h2 ~ section h1 ~ section h1 ~ section h1,
h2 ~ section h1 ~ section h2,
h2 ~ section h2 ~ section h1,
h2 ~ section h3,
h3 ~ section h1 ~ section h1,
h3 ~ section h2,
h4 ~ section h1,
h5 ~ section h3,
h5 ~ section h4 {
	color: blue;
  font-size: 1.25rem;
}

h6,
h1 ~ section h1 ~ section h1 ~ section h1 ~ section h1 ~ section h1,
h1 ~ section h1 ~ section h1 ~ section h1 ~ section h2,
h1 ~ section h1 ~ section h1 ~ section h2 ~ section h1,
h1 ~ section h1 ~ section h1 ~ section h3,
h1 ~ section h1 ~ section h1 ~ section h4,
h1 ~ section h1 ~ section h2 ~ section h1 ~ section h1,
h1 ~ section h1 ~ section h2 ~ section h2,
h1 ~ section h1 ~ section h3 ~ section h1,
h1 ~ section h1 ~ section h4,
h1 ~ section h2 ~ section h1 ~ section h1 ~ section h1,
h1 ~ section h2 ~ section h1 ~ section h2,
h1 ~ section h2 ~ section h2 ~ section h1,
h1 ~ section h2 ~ section h3,
h1 ~ section h3 ~ section h2,
h1 ~ section h3 ~ section h1 ~ section h1,
h1 ~ section h4 ~ section h1,
h1 ~ section h5,
h2 ~ section h1 ~ section h1 ~ section h1 ~ section h1,
h2 ~ section h1 ~ section h1 ~ section h2,
h2 ~ section h1 ~ section h1 ~ section h3,
h2 ~ section h1 ~ section h2 ~ section h1,
h2 ~ section h1 ~ section h3,
h2 ~ section h2 ~ section h2,
h2 ~ section h2 ~ section h3,
h2 ~ section h2 ~ section h1 ~ section h1,
h2 ~ section h3 ~ section h1,
h2 ~ section h3 ~ section h2,
h2 ~ section h4,
h2 ~ section h5,
h3 ~ section h1 ~ section h2,
h3 ~ section h1 ~ section h1 ~ section h1,
h3 ~ section h2 ~ section h1,
h3 ~ section h2 ~ section h2,
h3 ~ section h3,
h3 ~ section h3 ~ section h1,
h3 ~ section h3 ~ section h2,
h3 ~ section h4,
h3 ~ section h5,
h4 ~ section h2,
h4 ~ section h3,
h4 ~ section h4,
h4 ~ section h5,
h4 ~ section section h1,
h5 ~ section h1,
h5 ~ section h2,
h5 ~ section h3,
h5 ~ section h4,
h5 ~ section h5,
h6 ~ section h1,
h6 ~ section h2,
h6 ~ section h3,
h6 ~ section h4,
h6 ~ section h5 {
 	color: indigo; 
  font-size: 1rem;
}

templates.application.hbs

<h1>Heading 1</h1>

<section>
	<h1>Heading 1</h1>
  
  <section>
  	<h1>Heading 1</h1>
    
    <section>
      <h1>Heading 1</h1>
      
      <section>
      	<h1>Heading 1</h1>
        
        <section>
          <h1>Heading 1</h1>
          
          <section>
            <h1>Heading 1</h1>
            <h2>Heading 2</h2>
            <h3>Heading 3</h3>
            <h4>Heading 4</h4>
            <h5>Heading 5</h5>
            <h6>Heading 6</h6>
          </section>
        </section>
      </section>
    </section>
  </section>
</section>

tests.helpers.destroy-app.js

import { run } from '@ember/runloop';

export default function destroyApp(application) {
  run(application, 'destroy');
}

tests.helpers.start-app.js

import Ember from 'ember';
import Application from '../../app';
import config from '../../config/environment';

const { run } = Ember;
const assign = Ember.assign || Ember.merge;

export default function startApp(attrs) {
  let application;

  let attributes = assign({rootElement: "#test-root"}, config.APP);
  attributes.autoboot = true;
  attributes = assign(attributes, attrs); // use defaults, but you can override;

  run(() => {
    application = Application.create(attributes);
    application.setupForTesting();
    application.injectTestHelpers();
  });

  return application;
}

tests.test-helper.js

import Application from '../app';
import config from '../config/environment';
import { setApplication } from '@ember/test-helpers';
import { start } from 'ember-qunit';
import { assign } from '@ember/polyfills';

let attributes = assign({ rootElement: '#main' }, config.APP);
setApplication(Application.create(attributes));

start();

twiddle.json

{
  "version": "0.15.1",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.4.3",
    "ember-template-compiler": "3.4.3",
    "ember-testing": "3.4.3"
  },
  "addons": {
    "ember-data": "3.4.2"
  }
}