added scene transitions

styles/SceneTransition.css

@@ -0,0 +1,22 @@
+.SceneTransition {
+	position: absolute;
+	left: 0;
+	top: 0;
+	right: 0;
+	bottom: 0;
+	background: #333;
+	opacity: 0;
+	animation: scene-transition-fade-in 0.2s forwards;
+}
+.SceneTransition.fade-out {
+	animation: scene-transition-fade-out 0.2s forwards;
+}
+
+@keyframes scene-transition-fade-in {
+	from { opacity: 0; }
+	to { opacity: 1; }
+}
+@keyframes scene-transition-fade-out {
+	from { opacity: 1; }
+	to { opacity: 0; }
+}