how to set margins of children code example

Example 1: css prevent margin collapsing

/* Some CSS Properties that prevent margin collapsing (each of them does) */

float: left;
float: right;

position: absolute;

display: inline-block;
display: flex;

overflow: hidden;

Example 2: css space between child elements

/*
	this method will add bottom space but will not apply bottom space in last child
*/

div > *:not(:last-child) {
    display: block;
    margin-bottom: 30px; 
}