docs: add codesandbox to advanced banner example

Author: jscottsmith

documentation/docs/examples/advanced-banners.mdx

@@ -24,6 +24,12 @@ The following is a breakdown of some of the more advanced configuration for the
 4. Certain layers set `expanded` to `false`. This is because they don't move or have no edge that would appear visible so there is no need to expand them.
 5. Lastly, a gradient overlay is added to dim the scene with an `opacity` transition.
 
+:::info
+
+Here's a [CodeSandbox](https://codesandbox.io/s/mvzp1) with [full page banner](https://mvzp1.csb.app/) like the one above.
+
+:::
+
 ```tsx
 const Component = () => {
   const background: BannerLayer = {