align div vertical code example

Example 1: css center

// example 1 
div { display: grid; place-items: center; }

// example 3
div{ display:flex; align-items:center; }

// example 3
div { width: 100%; margin: 0 auto; }

Example 2: vertical align into div

#parent {position: relative;}

#child {
    position: absolute;
    top: 0;
    bottom: 0;
    left: 0;
    right: 0;
    width: 50%;
    height: 30%;
    margin: auto;
}

Example 3: 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; }