//HTML
<a class="btn-agent" href="javascript:void(0);">Agent View</a>
<a class="btn-client" href="javascript:void(0);">Client View</a>


// CSS
.client .agent, .client .arrow {
  display: none;
}

.client .upper {
  height: 100vh;
}

//JS
$('.btn-client').on('click', function (){
  $('body').addClass('client');
});

$('.btn-agent').on('click', function (){
  $('body').removeClass('client');
});