docs(card): adding info regarding the gradient for blurred card

apps/docs/content/docs/components/card.mdx

@@ -73,10 +73,12 @@ You can use other NextUI components inside the card to compose a more complex ca
 
 ### Blurred Card
 
-You can pass the `isBlurred` prop to the card to blur the card.
+You can pass the `isBlurred` prop to the card to blur the card. Card gets blurred properties with respect to its ansestor element.
 
 <CodeDemo isGradientBox title="Blurred Card" files={cardContent.blurred} />
 
+**Note** : While trying out the above example, it is required to provide necessary background to any ansestor element of Card Component in order to obtain the `blur` effect as seen in preview.
+
 ### Primary Action
 
 If you pass the `isPressable` prop to the card, it will be rendered as a button.