overlay an element in css code example
Example 1: css div overlay div
#container { //goes to the bottom
width: 100px;
height: 100px;
position: relative;
}
#div1{ //comes to the top
width: 100%;
height: 100%;
position: absolute;
top: 0;
left: 0;
z-index: 10;
}
Example 2: overlay a box in css
<html>
<body>
<div class="overlay"></div>
<body>
<html>