Using CSS Z-Index property developer can stack elements onto one another. Z-Index can have a positive or a negative value.
NOTE − If elements that overlap do not have z-index specified then that element will show up that is mentioned last in document.
Let’s see an example of z-index property −
Example
<!DOCTYPE html>
<html>
<head>
<style>
p {
background: url("https://www.tutorialspoint.com/arangodb/images/arangodb.jpg");
background-origin: content-box;
background-repeat: no-repeat;
background-size: cover;
box-shadow: 0 0 3px black;
padding: 20px;
background-origin: border-box;
}
</style>
</head>
<body>
<h2>ArangoDB</h2>
<p>ArangoDB is hailed as a native multi-model database by its developers. This is unlike other NoSQL databases. In this database, the data can be stored as documents, key/value pairs or graphs.
As a native multi-model database, ArangoDB eliminates the need to deploy multiple databases, and thus decreases the number of components and their maintenance. Consequently, it reduces the technology-stack complexity for the application. In addition to consolidating your overall technical needs, this simplification leads to lower total cost of ownership and increasing flexibility.</p>
</body>
</html>Output

Let’s see another example of z-index property −
Example
<!DOCTYPE html>
<html>
<head>
<style>
p {
margin: 0;
position: absolute;
top: 50%;
left: 50%;
transform: translate(-50%, -50%);
}
div{
margin: auto;
position: absolute;
top:0;
left: 0;
right: 0;
bottom: 0;
}
div:first-child {
background-color: orange;
width: 270px;
height: 120px;
z-index: -2;
}
div:last-child {
width: 250px;
height: 100px;
z-index: -1;
background-color: turquoise;
}
</style>
</head>
<body>
<div></div>
<p>Variables are the reserved memory locations to store values. This means that when you create a variable you reserve some space in memory.............</p>
<div></div>
</body>
</html>Output
