vertically align div in css code example

Example 1: css center

/* this will center all children within the parent element. */
.parent {
  display: flex;
  justify-content: center; /* horizontal */
  align-items: center; /* vertical */
}

Example 2: css center vertically

<style>
.container {
  height: 200px;
  position: relative;
  border: 3px solid green;
}

.center {
  margin: 0;
  position: absolute;
  top: 50%;
  left: 50%;
  -ms-transform: translate(-50%, -50%);
  transform: translate(-50%, -50%);
}
</style>

<div class="container">
  <div class="center">
    <p>I am vertically and horizontally centered.</p>
  </div>
</div>

Example 3: css center vertically

/* 100vh = 100% Viewport Height */
body {
	display: flex;
	height: 100vh;
	flex-direction: column;
	justify-content: center;
}
/* add */ align-items: center; /*to also center horizontally.*/

Example 4: vertical align div

HTML:
<div class="ext-box">
	<div class="int-box">
		<h2>Some txt</h2>
		<p>bla bla bla</p>
	</div>
</div>

CSS:
div.ext-box { display: table; height: 100%; width:100%;}
div.int-box { display: table-cell; vertical-align: middle; }