不透明性是较薄的油漆，需要添加黑色以增加不透明性。
以下示例显示CSS3 Opacity属性-
<html>
<head>
<style>
#m1 {background-color:rgb(255,0,0);opacity:0.6;}
#m2 {background-color:rgb(0,255,0);opacity:0.6;}
#m3 {background-color:rgb(0,0,255);opacity:0.6;}
</style>
</head>
<body>
<p>HSLA colors:</p>
<p id = "m1">Red</p>
<p id = "m2">Green</p>
<p id = "m3">Blue</p>
</body>
</html>