CSS FlexBox
It is mainly used to make CSS3 capable to change its item’s width and height to best fit all available spaces. It is preferred over the block model.
- Flex container: It is the property of the parent.The display property of an element to either flex or inline-flex.
- Flex items: It is the property of the children. One or more CSS flex items inside a flex container.

Example:
<!DOCTYPE html>
<html>
<head>
<style>
.flex-container {
display: -webkit-flex;
display: flex;
width: 400px;
height: 200px;
background-color: lightpink;
}
.flex-item {
background-color: gray;
width: 100px;
height: 100px;
margin: 10px;
color:white;
}
</style>
</head>
<body>
<div class="flex-container">
<div class="flex-item">flex item 1</div>
<div class="flex-item">flex item 2</div>
<div class="flex-item">flex item 3</div>
</div>
</body>
</html>
OUTPUT:

If you want to change the direction of the flex line by using the direction property.
Example:
<!DOCTYPE html>
<html>
<head>
<style>
body {
direction: rtl;
}
.flex-container {
display: -webkit-flex;
display: flex;
width: 400px;
height: 200px;
background-color: lightpink;
}
.flex-item {
background-color: gray;
width: 100px;
height: 100px;
margin: 10px;
color:white;
}
</style>
</head>
<body>
<div class="flex-container">
<div class="flex-item">flex item 1</div>
<div class="flex-item">flex item 2</div>
<div class="flex-item">flex item 3</div>
</div>
</body>
</html>
OUTPUT:
