transparent background css

.opacity30 {
  opacity: 0.3;
  filter: alpha(opacity=30); /* For IE8 and earlier */
}

/*fake background opacity css */
<div style="background-color:rgba(0, 0, 0, 0.5);">
   <div>
      Text added.
   </div>
</div>

/* Use RGBA */
background-color: rgba(255, 255, 0, 0.75); /* Transparent Yellow */

html,body {
  background-color: red;
}

background: rgba(255, 255, 255, 0.25);

img {
  opacity: 0.5;
}

body {
  background: #ffffff url("img_tree.png") no-repeat fixed right top;
}

div {
  width: 200px;
  height: 200px;
  display: block;
  position: relative;
}

div::after {
  content: "";
  background: url(image.jpg);
  opacity: 0.5;
  top: 0;
  left: 0;
  bottom: 0;
  right: 0;
  position: absolute;
  z-index: -1;   
}

div {
 opacity:25% ; 
}

The following example sets the opacity for the background color and not the text: 100% opacity. 60% opacity. 30% opacity. 10% opacity. You learned from our ...

img {
  opacity: 0.5;
}