Opa tenta fazer assim oh
<html>
<head>
<style>
div {
background-color: #4CAF50;
padding: 10px;
}
div.first {
opacity: 0.1;
}
div.second {
opacity: 0.3;
}
div.third {
opacity: 0.6;
}
</style>
</head>
<body>
<h1>Jesus é Bom</h1>
<p>Espero que lhe ajude =D</p>
<div class="first"><p>opacity 0.1</p></div>
<div class="second"><p>opacity 0.3</p></div>
<div class="third"><p>opacity 0.6</p></div>
<div><p>opacity 1 (default)</p></div>
</body>
<p>By TipsCode =D </p>
</html>