revamped and greatly simplified the layout of .slides

css/reveal.css

@@ -560,8 +560,11 @@ body {
 	position: absolute;
 	width: 100%;
 	height: 100%;
-	left: 50%;
+	top: 0;
-	top: 50%;
+	right: 0;
+	bottom: 0;
+	left: 0;
+	margin: auto;
 
 	overflow: visible;
 	z-index: 1;
@@ -576,10 +579,10 @@ body {
 	    -ms-perspective: 600px;
 	        perspective: 600px;
 
-	-webkit-perspective-origin: 0px -100px;
+	-webkit-perspective-origin: 50% 40%;
-	   -moz-perspective-origin: 0px -100px;
+	   -moz-perspective-origin: 50% 40%;
-	    -ms-perspective-origin: 0px -100px;
+	    -ms-perspective-origin: 50% 40%;
-	        perspective-origin: 0px -100px;
+	        perspective-origin: 50% 40%;
 }
 
 .reveal .slides>section {
@@ -640,11 +643,6 @@ body {
 	        transition-duration: 1200ms;
 }
 
-.reveal .slides>section {
-	left: -50%;
-	top: -50%;
-}
-
 .reveal .slides>section.stack {
 	padding-top: 0;
 	padding-bottom: 0;
@@ -1133,10 +1131,10 @@ body {
  *********************************************/
 
 .reveal.overview .slides {
-	-webkit-perspective-origin: 0% 0%;
+	-webkit-perspective-origin: 50% 50%;
-	   -moz-perspective-origin: 0% 0%;
+	   -moz-perspective-origin: 50% 50%;
-	    -ms-perspective-origin: 0% 0%;
+	    -ms-perspective-origin: 50% 50%;
-	        perspective-origin: 0% 0%;
+	        perspective-origin: 50% 50%;
 
 	-webkit-perspective: 700px;
 	   -moz-perspective: 700px;
@@ -1146,7 +1144,6 @@ body {
 
 .reveal.overview .slides section {
 	height: 600px;
-	top: -300px !important;
 	overflow: hidden;
 	opacity: 1 !important;
 	visibility: visible !important;

js/reveal.js

@@ -1118,7 +1118,11 @@ var Reveal = (function(){
 			}
 			// Apply scale transform as a fallback
 			else {
-				transformElement( dom.slides, 'translate(-50%, -50%) scale('+ scale +') translate(50%, 50%)' );
+				dom.slides.style.left = '50%';
+				dom.slides.style.top = '50%';
+				dom.slides.style.bottom = 'auto';
+				dom.slides.style.right = 'auto';
+				transformElement( dom.slides, 'translate(-50%, -50%) scale('+ scale +')' );
 			}
 
 			// Select all slides, vertical and horizontal
@@ -1139,7 +1143,7 @@ var Reveal = (function(){
 						slide.style.top = 0;
 					}
 					else {
-						slide.style.top = Math.max( - ( getAbsoluteHeight( slide ) / 2 ) - slidePadding, -slideHeight / 2 ) + 'px';
+						slide.style.top = Math.max( ( ( slideHeight - getAbsoluteHeight( slide ) ) / 2 ) - slidePadding, 0 ) + 'px';
 					}
 				}
 				else {