Update theme with: 1. Tiles: (add white bg in default). 2. Notifications: like alerts with shadow. 3. Tooltip: Add shadow. 4. Card: add border-radius in header and footer

css/structure/tile.css

@@ -0,0 +1,11 @@
+.uk-tile-default {
+  background-color: var(--light-color);
+}
+
+.uk-tile-primary {
+  background-color: var(--primary-color);
+}
+
+.uk-tile-secondary {
+  background-color: var(--secondary-color);
+}