Youtube

<style>

  
  

div input { margin-right: 100px; }

.check-btn label { display: inline-block; }

.check-btn input { display: none; }

.clicker { background:eee; padding: 1px 3px; }

.hiddendiv { background: transparent; width: 100px; height: 100px; display: none; }

.check-btn input:checked ~ .hiddendiv { display: block; }

<input id="myid" type="checkbox" >
<label for="myid" class="clicker">doremi💜</label>
<div class="hiddendiv">    <iframe style="width:inherit; height:inherit; border:0;" src="https://www.youtube.com/embed/fMFNcoiG8Ok"></iframe></div>