horizontally center a div in the body code example

Example 1: how to align elements horizontally in css

.row {
  width: 100%;
  display: flex;
  flex-direction: row;
  justify-content: center;
}
.block {
  width: 100px;
}

Example 2: how to center horizontally and vertically block div

#html code
<div class="parent">
	<h1 class="child">CSS is cool</h1>
</div>

#css code
.parent{
  display:grid;
  place-items:center;
  
  width:560px; 
  height: 560px;
}