JSFiddle - React, Tailwind, and code Playground

HTML

<div class="container">
        <div id="red" class="span6" style="background: red;width:40%;float:left;margin-right:5%;">
            Block 1 - Vertically center me please!<br />
            Lorem Ipsum is simply dummy text of the printing and typesetting industry. Lorem Ipsum has been the industry's standard dummy text ever since the 1500s, when an unknown printer took a galley of type and scrambled it to make a type specimen book. 
        </div>
        <div id="blue" class="span6" style="background: blue;width:40%;float:left;">
            Block 2- Center me too<br />
            Contrary to popular belief, Lorem Ipsum is not simply random text.
        </div>
    </div>

JavaScript

$(document).ready(function() {
	var ver_top = ($(window).height() - $('#red').height()) / 2;
	$('#red').css( "margin-top", ver_top+'px' );
	
	var ver_top2 = ($(window).height() - $('#blue').height()) / 2;
	$('#blue').css( "margin-top", ver_top2+'px' );
	
	$(window).resize(function(){
		var ver_top = ($(window).height() - $('#red').height()) / 2;
		$('#red').css( "margin-top", ver_top+'px' );
		
		var ver_top2 = ($(window).height() - $('#blue').height()) / 2;
		$('#blue').css( "margin-top", ver_top2+'px' );
	});
});