diff --git a/css/reveal.css b/css/reveal.css
index 3a31fa4..b203074 100644
--- a/css/reveal.css
+++ b/css/reveal.css
@@ -20,7 +20,7 @@ html, body, .reveal div, .reveal span, .reveal applet, .reveal object, .reveal i
 .reveal article, .reveal aside, .reveal canvas, .reveal details, .reveal embed,
 .reveal figure, .reveal figcaption, .reveal footer, .reveal header, .reveal hgroup,
 .reveal menu, .reveal nav, .reveal output, .reveal ruby, .reveal section, .reveal summary,
-.reveal time, .reveal mark, .reveal audio, video {
+.reveal time, .reveal mark, .reveal audio, .reveal video {
   margin: 0;
   padding: 0;
   border: 0;
@@ -989,7 +989,8 @@ html:-moz-full-screen-ancestor {
   -webkit-perspective: 700px;
           perspective: 700px; }
   .reveal.overview .slides section {
-    height: 700px;
+    height: 100%;
+    top: 0 !important;
     opacity: 1 !important;
     overflow: hidden;
     visibility: visible !important;
diff --git a/css/reveal.scss b/css/reveal.scss
index 8cf8cda..f8d6904 100644
--- a/css/reveal.scss
+++ b/css/reveal.scss
@@ -1022,7 +1022,8 @@ html:-moz-full-screen-ancestor {
 	perspective: 700px;
 
 	.slides section {
-		height: 700px;
+		height: 100%;
+		top: 0 !important;
 		opacity: 1 !important;
 		overflow: hidden;
 		visibility: visible !important;
diff --git a/js/reveal.js b/js/reveal.js
index 0b1cad7..96a6359 100644
--- a/js/reveal.js
+++ b/js/reveal.js
@@ -166,6 +166,10 @@
 		// Flags if the overview mode is currently active
 		overview = false,
 
+		// Holds the dimensions of our overview slides, including margins
+		overviewSlideWidth = null,
+		overviewSlideHeight = null,
+
 		// The horizontal and vertical index of the currently active slide
 		indexh,
 		indexv,
@@ -1798,6 +1802,17 @@
 				}
 			} );
 
+			// Calculate slide sizes
+			var margin = 70;
+			var slideSize = getComputedSlideSize();
+			overviewSlideWidth = slideSize.width + margin;
+			overviewSlideHeight = slideSize.height + margin;
+
+			// Reverse in RTL mode
+			if( config.rtl ) {
+				overviewSlideWidth = -overviewSlideWidth;
+			}
+
 			updateSlidesVisibility();
 			layoutOverview();
 			updateOverview();
@@ -1821,19 +1836,10 @@
 	 */
 	function layoutOverview() {
 
-		var margin = 70;
-		var slideWidth = config.width + margin,
-			slideHeight = config.height + margin;
-
-		// Reverse in RTL mode
-		if( config.rtl ) {
-			slideWidth = -slideWidth;
-		}
-
 		// Layout slides
 		toArray( dom.wrapper.querySelectorAll( HORIZONTAL_SLIDES_SELECTOR ) ).forEach( function( hslide, h ) {
 			hslide.setAttribute( 'data-index-h', h );
-			transformElement( hslide, 'translate3d(' + ( h * slideWidth ) + 'px, 0, 0)' );
+			transformElement( hslide, 'translate3d(' + ( h * overviewSlideWidth ) + 'px, 0, 0)' );
 
 			if( hslide.classList.contains( 'stack' ) ) {
 
@@ -1841,7 +1847,7 @@
 					vslide.setAttribute( 'data-index-h', h );
 					vslide.setAttribute( 'data-index-v', v );
 
-					transformElement( vslide, 'translate3d(0, ' + ( v * slideHeight ) + 'px, 0)' );
+					transformElement( vslide, 'translate3d(0, ' + ( v * overviewSlideHeight ) + 'px, 0)' );
 				} );
 
 			}
@@ -1849,10 +1855,10 @@
 
 		// Layout slide backgrounds
 		toArray( dom.background.childNodes ).forEach( function( hbackground, h ) {
-			transformElement( hbackground, 'translate3d(' + ( h * slideWidth ) + 'px, 0, 0)' );
+			transformElement( hbackground, 'translate3d(' + ( h * overviewSlideWidth ) + 'px, 0, 0)' );
 
 			toArray( hbackground.querySelectorAll( '.slide-background' ) ).forEach( function( vbackground, v ) {
-				transformElement( vbackground, 'translate3d(0, ' + ( v * slideHeight ) + 'px, 0)' );
+				transformElement( vbackground, 'translate3d(0, ' + ( v * overviewSlideHeight ) + 'px, 0)' );
 			} );
 		} );
 
@@ -1864,19 +1870,10 @@
 	 */
 	function updateOverview() {
 
-		var margin = 70;
-		var slideWidth = config.width + margin,
-			slideHeight = config.height + margin;
-
-		// Reverse in RTL mode
-		if( config.rtl ) {
-			slideWidth = -slideWidth;
-		}
-
 		transformSlides( {
 			overview: [
-				'translateX('+ ( -indexh * slideWidth ) +'px)',
-				'translateY('+ ( -indexv * slideHeight ) +'px)',
+				'translateX('+ ( -indexh * overviewSlideWidth ) +'px)',
+				'translateY('+ ( -indexv * overviewSlideHeight ) +'px)',
 				'translateZ('+ ( window.innerWidth < 400 ? -1000 : -2500 ) +'px)'
 			].join( ' ' )
 		} );