body {margin: 0;padding: 0;font-family: Arial, Helvetica, sans-serif;}
div#preload{
	position: fixed;
	width: 100%; height: 100%;
	top: 0; left: 0;
	padding-top: 25%;
	background: #f2f2f3;
	z-index: 1
}
div#preload h1, div#preload h2{text-align: center;}
div#images{height: 5000px; z-index: 0;}
img{
    /* goc */ 
    position: fixed;
    min-height: 100%; width: auto;
    top: 50%; left: 50%; transform: translate(-50%, -50%)
    /* thay doi 1 
    position: fixed;
    width: 100%; height: auto;
    max-width: 800px;
	*/
	/* thay doi 2
	position: fixed;
	width: 100%; height: auto;	
	top: 50%; left: 50%; transform: translate(-50%, -50%);
	*/
}