Make weekday names brighter, lighter month/year title.

Signed-off-by: Marin Treselj <marin@pixelipo.com>

core/css/styles.scss

@@ -979,7 +979,7 @@ code {
 	.ui-widget-header {
 		padding: 7px;
 		font-size: 13px;
-		font-weight: normal;
+		font-weight: 300;
 		border:	none;
 		background-color: $color-main-background;
 		color: $color-main-text;
@@ -1005,6 +1005,7 @@ code {
 		th {
 			font-weight: normal;
 			color: nc-lighten($color-main-text, 33%);
+			opacity: .8;
 		}
 		tr:hover {
 			background-color: inherit;
@@ -1034,6 +1035,7 @@ code {
 			&.ui-datepicker-week-end :not(.ui-state-hover),
 			.ui-priority-secondary:not(.ui-state-hover) {
 				color: nc-lighten($color-main-text, 33%);
+				opacity: .8;
 			}
 		}
 	}