Simplified CSS3DRenderer Object3D CSSMatrix. Thanks @brendankenny.

examples/js/renderers/CSS3DRenderer.js

@@ -121,10 +121,10 @@ THREE.CSS3DRenderer = function () {
 			epsilon( elements[ 1 ] ) + ',' +
 			epsilon( elements[ 2 ] ) + ',' +
 			epsilon( elements[ 3 ] ) + ',' +
-			epsilon( elements[ 4 ] ) + ',' +
-			epsilon( elements[ 5 ] ) + ',' +
-			epsilon( elements[ 6 ] ) + ',' +
-			epsilon( elements[ 7 ] ) + ',' +
+			epsilon( - elements[ 4 ] ) + ',' +
+			epsilon( - elements[ 5 ] ) + ',' +
+			epsilon( - elements[ 6 ] ) + ',' +
+			epsilon( - elements[ 7 ] ) + ',' +
 			epsilon( elements[ 8 ] ) + ',' +
 			epsilon( elements[ 9 ] ) + ',' +
 			epsilon( elements[ 10 ] ) + ',' +
@@ -133,7 +133,7 @@ THREE.CSS3DRenderer = function () {
 			epsilon( elements[ 13 ] ) + ',' +
 			epsilon( elements[ 14 ] ) + ',' +
 			epsilon( elements[ 15 ] ) +
-		') scale3d(1,-1,1)';
+		')';
 
 	}