fix pause overlay

css/reveal.scss

@@ -1073,7 +1073,7 @@ $controlsArrowAngleActive: 36deg;
 	background: black;
 	visibility: hidden;
 	opacity: 0;
-	z-index: 100;
+	z-index: 10001;
 	transition: all 1s ease;
 }
 

js/controllers/keyboard.js

@@ -190,7 +190,7 @@ export default class Keyboard {
 			}
 		}
 
-		if( this.Reveal.isOverlayOpen() && !['Escape', 'f', 'c'].includes(event.key) ) {
+		if( this.Reveal.isOverlayOpen() && !["Escape", "f", "c", "b", "."].includes(event.key) ) {
 			return false;
 		}