Center the contents of a html page

flexbox-center.css

html, body { height: 100% /* html also needs height:100% */ }

body {
	display: -moz-box;
	-moz-box-pack: center;
	-moz-box-align: center;
	-moz-box-orient: vertical;

	display: -webkit-box;
	-webkit-box-pack: center;
	-webkit-box-align: center;
	-webkit-box-orient: vertical;

	display: box;         /* enable box- properties */
	box-pack: center;     /* center vertically */
	box-align: center;    /* center horizontally */
	box-orient: vertical; /* default is horizontal stacking */

	width: 100%;          /* display:box makes width collapse */
	margin: 0;            /* body has a margin by default and will make scrollbars appear */
}