JSFiddle - React, Tailwind, and code Playground

HTML

<script src="https://unpkg.com/[email protected]/dist/vue.min.js"></script>
<link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/3.3.7/css/bootstrap.min.css">
<div id="app"> 
  <transition name="fade">
    <div v-if="switc">
      <div style="background-color: pink; height: 100px"></div>
   </div>
   </transition>
   <button type="button" class="btn btn-secondary" @click="switc = !switc">
     <span>Switch</span>
   </button>
</div>

CSS

.fade-enter-active, .fade-leave-active {
  transition: all .5s;
  height: 100px;
  opacity: 0.5;
}
.fade-enter, .fade-leave-to /* .fade-leave-active in <2.1.8 */ {
  height: 0px;
  opacity: 0;
}

JavaScript

var app = new Vue({
  el: '#app',
  data: {    
      switc: false
  }
})