Flex box margin transition

controllers.application.js

import Ember from 'ember';

export default Ember.Controller.extend({
  appName: 'Ember Twiddle',
  
  actions: {
    toggle() {
     	this.toggleProperty('isIn'); 
    }
  }  
  

});

styles.app.css

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

.either {
  transition: all 0.5s ease-in-out;
}
.in {
  margin-left: -200px; 
}

.out {
  margin-left: 100px;
}

templates.application.hbs

<h1>Slidin</h1>
<br>
<br>
{{outlet}}
<div style="display: flex; justify-content: space-around">
	<div style="border: 1px solid #000; width: 100px; height: 100px; width: 800px; height: 1000px; background-color: blue"></div>
  <div style="width: 200px">
	  <div style="border: 1px solid #000; width: 100px; height: 100px; background-color: red" class="either {{if isIn 'in' 'out'}}"> 
<button {{action 'toggle'}}>
Click
</button>
    </div>
  </div>
</div>
<br>
<br>

twiddle.json

{
  "version": "0.15.0",
  "EmberENV": {
    "FEATURES": {}
  },
  "options": {
    "use_pods": false,
    "enable-testing": false
  },
  "dependencies": {
    "jquery": "https://cdnjs.cloudflare.com/ajax/libs/jquery/3.3.1/jquery.js",
    "ember": "3.2.2",
    "ember-template-compiler": "3.2.2",
    "ember-testing": "3.2.2"
  },
  "addons": {
    "ember-data": "3.2.0"
  }
}