JSFiddle - React, Tailwind, and code Playground

HTML

<link rel="stylesheet" href="http://netdna.bootstrapcdn.com/bootstrap/3.0.0/css/bootstrap.min.css">
<script src="https://ajax.googleapis.com/ajax/libs/angularjs/1.2.1/angular-animate.min.js"></script>
<div ng-app="app" ng-init="left = true">
  <div class="row">
      <div class="col-md-{{left ? 8 : 4}} left column" ng-click="left = true">
          Left Side
      </div>
      <div class="col-md-{{left ? 4 : 8}} right column" ng-click="left = false">
          Right Side
      </div>
  </div>
</div>

CSS

.left  {
  background-color: #EEE;
}

.right {
  background-color: #CCC;
}

.column {
  transition: width 1s;
}

JavaScript

// Make sure to grow the "Result" window so that the left and right show up as columns
// Click on a column to watch the CSS animation get all funky
// Remove ngAnimate below, and watch it work properly

var app = angular.module('app', ['ngAnimate']);

app.controller('TestCtrl', function($scope) {
    
});