If in any case we need to call a background image before a div this css code will be used to execute it.
Example:
calling background image before shipping address in the checkout page for showing the progress step.

Single dot before the shipping address.
It can be achieved by the following css commands:
/*main class*/
.checkout-index-index .step-title {
padding-left: 30px;
margin-left: -24px;
position: relative;
}
/*main class with before tag*/
.checkout-index-index .step-title::before{
width: 27px;
height: 27px;
content: " ";
left: 0;
position: absolute;
background-position: left;
background-image: url('../images/Ellipse.svg');
}
Position relative for the main class and position absolute for the before div class.