prefer vh for speaker notes layout

css/reveal.css

@@ -1531,19 +1531,24 @@ body {
     border-left: 0;
     max-width: none;
     max-height: 70%;
+    max-height: 70vh;
     overflow: visible; }
   .reveal.show-notes .speaker-notes {
     top: 100%;
     left: 0;
     width: 100%;
-    height: 42.8571428571%; } }
+    height: 42.8571428571%;
+    height: 30vh;
+    border: 0; } }
 
 @media screen and (max-width: 600px) {
   .reveal.show-notes {
-    max-height: 60%; }
+    max-height: 60%;
+    max-height: 60vh; }
   .reveal.show-notes .speaker-notes {
     top: 100%;
-    height: 66.6666666667%; }
+    height: 66.6666666667%;
+    height: 40vh; }
   .reveal .speaker-notes {
     font-size: 14px; } }
 

css/reveal.scss

@@ -1684,6 +1684,7 @@ $controlsArrowAngleActive: 36deg;
 		border-left: 0;
 		max-width: none;
 		max-height: 70%;
+		max-height: 70vh;
 		overflow: visible;
 	}
 
@@ -1692,17 +1693,21 @@ $controlsArrowAngleActive: 36deg;
 		left: 0;
 		width: 100%;
 		height: (30/0.7)*1%;
+		height: 30vh;
+		border: 0;
 	}
 }
 
 @media screen and (max-width: 600px) {
 	.reveal.show-notes {
 		max-height: 60%;
+		max-height: 60vh;
 	}
 
 	.reveal.show-notes .speaker-notes {
 		top: 100%;
 		height: (40/0.6)*1%;
+		height: 40vh;
 	}
 
 	.reveal .speaker-notes {