Add documentation about combining sprinkles and styles (#447)

Author: tvanantwerp

site/docs/sprinkles-api.md

@@ -342,6 +342,27 @@ export const sprinkles = createSprinkles(
 );
 ```
 
+As the sprinkles function returns a standard class list, you can combine it with a custom style using [style composition](/documentation/styling-api/#style).
+
+```ts
+// button.css.ts
+import { style } from '@vanilla-extract/css';
+import { sprinkles } from './sprinkles.css';
+
+export const button = style([
+  sprinkles({
+    paddingX: 'medium',
+    paddingY: 'small'
+  }),
+  {
+    transition: 'transform 0.2s ease-in-out',
+    ':hover': {
+      transform: 'scale(1.1)'
+    }
+  }
+]);
+```
+
 The sprinkles function also exposes a static `properties` key that lets you check whether a given property can be handled by the function.
 
 ```ts