Support fading elements with a previously set opacity without flicker

app/stylus/keyframes.styl

@@ -3,16 +3,17 @@
 		opacity: 0;
 		visibility: hidden;
 	}
+
  	to {
-		opacity: 1;
 		visibility: visible;
 	}
 }
+
 @keyframes fade-out {
 	from {
-		opacity: 1;
 		visibility: visible;
 	}
+
 	to {
 		opacity: 0;
 		visibility: hidden;