HTML CSS
(real quick examples)
<style> p.ghost { color: rgba(0, 0, 0, 0.5); } </style> <p class="ghost">Transparent Text.</p>
<style> div.ghost { background: rgba(0, 0, 0, 0.5); } </style> <div class="ghost"> Transparent Background. </div>
<style> img.ghost { opacity: 0.5; } </style> <img class="ghost" src="IMAGE.JPG"/>