css display div vertically center and horizontally on page code example

Example 1: vertically and horizontally center a fixed div

// you dont need to know the divs dimensions and it does not require any container divs
position: fixed; 
top: 50%;
left: 50%;
transform: translate(-50%, -50%);

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;
}