how to align elements in css code example

Example 1: css align center

//HTML
<div class="parent">
	<span>Hello World</span>
</div>

//CSS
.parent {
  display: flex;
  justify-content: center;
  align-items: center;
}

Example 2: css align items vertical center

.parent {
  display: flex;
  justify-content: center;
  align-items: center;
}

Example 3: css center text in div

/* For horizontal align: */
parent-element {text-align:center;}
/* For horizontal and vertical align: */
parent-element {position: relative;}
element-to-be-centered {
  position: absolute;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

/* See https://www.w3schools.com/css/css_align.asp for more info */

Example 4: how to center a div vertically and horizontally

.container{	
	margin: 0;
    position: absolute;
    top: 50%;
    left: 50%;
    -ms-transform: translate(-50%, -50%);
    transform: translate(-50%, -50%);
  	width: /* Define the width here; */
    height: /* Define the height here; */
}

/*You have to define the width and height! */