how to have no white space in css code example

Example 1: not last child css

p:not(:last-child) { 
	margin-bottom: 20px
}

Example 2: empty string css

.heart::before {
    content: "";
    background-color: pink;
    border-radius: 50%;
    position: absolute;
    width: 50px;
    height: 50px;
    top: -25px;
    left: 0px;